I didn't ask what version of the Deployment Framework you're using. I'm assuming v5.5. There's nothing special about this application of WiX. WixUIExtension.dll is already referenced, so any WiX UI is available.
You've edited the copy of GenericBizTalkMSI.wxs in your deployment project folder to replace <UIRef Id="WixUI_InstallDir" /> with <UIRef Id="WixUI_Mondo" />, removed <Property Id="WIXUI_INSTALLDIR" Value="INSTALLDIR" />, and you don't see any change in the UI?
Tom
You've edited the copy of GenericBizTalkMSI.wxs in your deployment project folder to replace <UIRef Id="WixUI_InstallDir" /> with <UIRef Id="WixUI_Mondo" />, removed <Property Id="WIXUI_INSTALLDIR" Value="INSTALLDIR" />, and you don't see any change in the UI?
Tom