I hope to write a more complete step-by-step guide for this, but in a nutshell:
1. Go to Dell.com and search for DTK 2.5 (as of this post) and download the executable.
2. Install Windows AIK (this one is for WinPE 2.0). You need MSXML 6.0 as well.
3. Extract the DTK.
4. Wherever you extract this, there will be a Dell\Drivers\winpe2.x folder. Go into that folder and execute VPE_driverinst.bat E:\winpe20_1750 E:\Dell\Drivers
NOTE: The first argument is a folder where this batch script will put the resulting WinPE image with all the Dell drivers and utilities. The second argument is Dell\Drivers in wherever you extracted the DTK to. This step takes about 5 minutes and is pretty verbose.
5. Backup C:\Program Files\Windows AIK\Tools\PETools\x86 and make a copy with the same folder name "x86". Now, overwrite the winpe.wim with the winpe.wim that the Dell batch script created in E:\winpe20_1750 or whatever folder you chose.
6. Use Provisioning Manager to create the image (this example is for x86, so obviously you must do the same as above for x64 if you decide to go that route as well).
7. Now in your system package pre-install scripts you can add a script that does something like this:
This batch script is one provided by Dell that uses a little smarts to provide some default configs. To get more advanced check out the CLI docs in the DTK download. Then you can just use the raidcfg.exe and do more crazy stuff. There are similar exe's and bat's for RAC, BIOS and BMC.