Making full portable an app which requires XAudio2

Hi to all:
I am trying to portabilize some PC games to transport in a big pendrive. Some of them requires a XAudio2_#.dll for ingame audio. But the question is that these files need 3 registry keys in HKEY_CLASSES_ROOT. These keys contains a full path to file (C:\Windows\system32\XAudio2_#.dll) and I don't know the game detect the file dll. Any chance to do it?
Thanks