Ok guys, this is tried and true....
First, download the Seismovision 2.26 Full client and install it.
Then, download the Seismovision 2.27 BETA 1 client and install it.
Make sure you download the update for the Seismovision CoD file.
After it's all installed, open up Seismovision, and change the Call of Duty .exe file to your CoDUOMP.exe file.
You HAVE to play the demos through the playlist however, not simply double clicking the icon.
Yes, fast forward, etc works.
Enjoy!
Here's the fix for CoD: United Offensive
Moderator: OomJan