I have encountered the same problem under W2k, but I don't think that the DP_MassStorage_wnt5_x86-32.ini is the reason why the drivers are not integrated, because ALL slipstreamed drivers get commented out in the txtsetup.sif and dosnet.inf, without regard to the " ms_1_exc_disableIfOS= "w2k" " expression.
Part of the txtsetup.sif
;vmscsi="VMware SCSI Controller"
;videX32="VIA SATA/PATA IDE controllers"
;viapdsk="VIA ATA/ATAPI Host Controller"
;viamraid="VIA RAID Controllers"
;sisraid2="SiS 182 RAID Controller"
;sisraid="SiS 180 RAID Controller"
;sisraid1="SiS 181 RAID Controller"
;si3132r5="Silicon Image 3132 SoftRaid 5 Controller"
;si3132="Silicon Image 3132 SATALink Controller"
;si3124r5="Silicon Image 3124 SoftRaid 5 Controller"
;si3124r="Silicon Image 3124 SATARaid Controller"
;si3124="Silicon Image 3124 SATALink Controller"
;si3114r="Silicon Image 3114 SATARaid Controller"
;si3114r5="Silicon Image 3114 SoftRaid 5 Controller"
;si3114="Silicon Image 3114 SATALink Controller"
;ati3112r="Silicon Image 3112 SATARaid Controller for ATI chipsets"
;si3112r="Silicon Image 3112 SATARaid Controller"
;si3112="Silicon Image 3112 SATALink Controller"
;pnp680r="Silicon Image 0680 Ultra-133 Medley ATA Raid Controller"
;pnp680="Silicon Image 0680 ATA/133 Controller"
;pnp649r="CMD PCI-0649 Ultra100 IDE Raid Controller"
;ql12160="QLogic QLA12160, 64 bit PCI DUAL 160M SCSI HBA"
;ql2300="QLogic QLA23xx PCI Fibre Channel Adapter"
;ql2200="QLogic QLA2200 PCI Fibre Channel Adapter"
;ql2100="QLogic QLA2000/QLA2100 PCI Fibre Channel Adapter"
;ultra="Promise SATAII150 TX2plus IDE Controller"
;ulsata2="Promise SATAII150 TX2plus IDE Controller"
;ulsata="Promise SATA150 TX Series IDE Controller"
;sptrak="Promise SuperTrak SX6000 IDE RAID Controller"
;fastsx="Promise FastTrak S150 SX4/SX4000 Series"
;s150sx8="Promise SATAII150 SX8 Controller"
;aftx2k="Promise FastTrak 376/378 Controller"
;fasttx2k="Promise FastTrak fasttx2k Controller"
;fasttrak="Promise FastTrak Controller"
;nvraid="NVIDIA nForce RAID Class Controller"
;nvatabus="NVIDIA NForce Storage Controller"
;mv614x="Marvell RAID 614x SATA2 Controller"
;symmpi="LSI Adapter, FC 4000 series, Dual or Quad port (with 929)"
;dac960nt="Mylex DAC960PG/PJ/PR/PT/PTL1/PRL Series Disk Array Controller"
;dac2w2k="Mylex AcceleRAID 160 Disk Array Controller"
;megaide="LSI MegaRAID IDE Controllers"
;videX32="VIA SATA/PATA IDE controllers"
;jraid="JMicron JMB36X RAID Controller"
;jahci="JMicron 20360/20363 AHCI Controller"
;iteraid="ITE IT8212 ATA RAID Controller"
;raidsrc="Intel SCSI RAID Controllers"
;iastrold="Intel 82801ER and 6300ESB SATA RAID Controllers"
;iastor="Intel SATA RAID Controllers"
;nfrd960="IBM i960-based IBM ServeRAID Adapters"
;ipsraidn="IBM ipsraidn ServeRAID Adapters"
;rr2310="HighPoint RocketRAID 2310 SATA Controller"
;rr404="HighPoint RocketRAID 404/454 ATA RAID (HPT374) Controller"
;rr2320="HighPoint RocketRAID 2320 SATA Controller"
;hptmv6="Highpoint RocketRAID 2220 SATA Controller"
;hpt366="Highpoint Hpt366 Ultra DMA 66 Controller"
;hptmv="HighPoint RocketRAID 182x SATA Controller"
;hpt374="HighPoint RocketRAID 154x/1640 Controller"
;rhpt3xx="HighPoint RocketRAID 1520 S-ATA Controller"
;hpt3xx="HighPoint RocketRAID 100/133 ATA RAID (HPT3xx) Controller"
;cercsr6="DELL CERC SATA 1.5/6ch RAID Controller"
;m5289="ALi/ULi M5289 SATA/RAID Controller (M1689/M1567)"
;m5288="ALi/ULi M5288 SATA/RAID Controller (M1575/M1697)"
;m5287="ALi/ULi M5287 SATA/RAID Controller (M1573)"
;m5281="ALi/ULi M5281/M5283 SATA/RAID Controller"
;m5228="ALi/ULi M5228 ATA/RAID Controller"
;arcm_x86="ARECA PCI RAID CARDS"
;amdbusdr="AMD PCI Bus Master IDE Controllers"
;aarich="Adaptec Embedded Serial ATA HostRAID Controller"
;cda1000="Adaptec Ultra320 SCSI Controllers"
;a320raid="Adaptec PCI SCSI HOSTRaid Controllers"
;aadpu320="Compaq PCI-X 133MHz 2CH U320 SCSI Adapter"
;adpu320="Adaptec Ultra320 SCSI Controllers"
;adpu160m="Adaptec Ultra160 SCSI Controllers"
;dpti2o="Adaptec I2O RAID Host Controllers"
;aar1210="Adaptec Serial ATA HostRAID Controller"
;aac="Adaptec SATA/SCSI RAID Controllers"
;ahpt3xx="Adaptec ATA RAID 1200A Controller"
;aec671x="ACARD AEC671X PCI Ultra/W SCSI Controller"
;aec67160="ACARD AEC67160 PCI Ultra160 LVD/SE SCSI Adapter"
;aec6897="AEC6897/6898 4-Channel IDE ULTRA 133/SERIAL ATA RAID Adapter"
;aec6880="ACARD AEC-6880/6890 Ultra ATA133 / Serial ATA RAID Controller"
;aec68x5="ACARD AEC-6885/6895/6896 PCI 4 Channel RAID Controller"
;aec6280="ACARD AEC6280/6290 ULTRA ATA133 IDE/Serial ATA Controller"
;aec6260="ACARD AEC6260 UltraDMA-66 Controller"
;aec6210="ACARD AEC6210UF UltraDMA33 Controller"
;3waregsm="3ware Escalade 6000 Storage Switch"
;3ware9k="AMCC 3ware 9000 Series ATA RAID Controller"
;3ware95k="AMCC 3ware 9000/9500 Series SATA RAID Controller"Consequently none of the drivers will work.
Could it be that there is a bug in the dpbase, which does not interprete the W2k-disable option in the DP_MassStorage_wnt5_x86-32.ini correctly and disables all mass-storage drivers for W2K???