Here, are instructions for integrating the Hyper-V RTM (!) Integration Components device drivers into a WinPE image.  This is based on Mike Sterling's post on the same topic, however the scripts below have been updated to use RTM Hyper-V bits.

1. Create your WinPE build folder, if you haven't already done so.  See Building a WinPE Image from Scratch for help (follow only steps 1 through 5).
2. In the root of your build folder, download the appropriate integration batch file from the bottom of this post.
3. Locate Windows6.0-KB951634-x86.msu.  This file is on the c:\windows\system32\vmguest.iso, located on any Hyper-V enabled host.  The update file should be located in the Support folder of the ISO.  Copy this file to the root of your WinPE build folder - the same location as your integration batch script.
4. From the Windows PE Tools Command Prompt, execute the integration script.  If everything went correctly, you'll see "PEIMG completed the operation successfully." listed seven times in the output of the script.
5. At this point your WinPE build is updated.  Resume steps 7 through 9 in Building a WinPE Image from Scratch to complete the process.

If you have questions about the above, please e-mail me at jason.huitt@colostate.edu - I've run both of these scripts successfully as of today, and now have working x86 and x64 WinPE ISOs.  My trust WinPE flash drive has been updated as well.  You'll love the integrated mouse and NIC support when building Hyper-V VMs.  No more Legacy Network Adapter!

Integrate_x86.bat (1.10 kb)

Integrate_x64.bat (1.12 kb)