Adding DD11 to an existing WinPE

Anybody managed to add DD11 to an existing WinPE image?

I had an existing bootable USB memory stick that already had TrueImage 2011 on it. I wanted to add DD11 to it. So I ran Media Builder and selected WinPE with the "use WinPE files located in the folder I specify" option. On the next dialog I pointed to my existing wim file. No go: "The selected folder does not contain the required WinPE files".

I tried all kinds of variations on the theme but couldn't get the "use WinPE files located in the folder I specify" option to work, even when I pointed to the default wim file (C:\Program Files\Windows AIK\Tools\PETools\x86\winpe.wim). Only "Create WinDows PE 2.0 or 3.0 automatically" worked for me. But I don't want Acronis to create WinPE for me. I've built a WinPE on my own steam and I only want media builder to add DD11 to it. Worked great with TrueImage Plus Pack. TI PlusPack and DD11 both come with a Media Builder and they look very much alike, both have the option to either build a new WinPE or use an existing WinPE. Except that DD11's option to use an existing WinPE appears to be broken.

In the end, the workaround that I found is copy my existing wim file to C:\Program Files\Windows AIK\Tools\PETools\x86, call it winpe.wim and use the "Create WinDows PE 2.0 or 3.0 automatically" option. So I achieved my goal in the end - build my own WinPE, then add both TI and DD to it - but it was via a rather tortuous path...

My Acronis products are the latest home versions, installed on Win7 X64.