Converted a DELL PowerEdge 1950 today and got some problems from VMWare Converter saying "Operating system not found".
I suspected it could be the Raid Drivers that was missing and the converter could not see the disk.
I downloaded the drivers for DELL PERC 6/i Integrated from Dell Support executed the file wich extracted the driverfiles to c:\dell\drivers\R194151
Then add the driverfiles to the iso with the petool.exe:

"petool.exe -i coldclone.iso -d C:\dell\drivers\R194151"

Burned the iso to a blanc cd-r and booted up with the CD. Worked perfect and vmware converter found the disks.