Garena Plus has been patched to work with generals. I have tried it and it works.
Go here for article:
Download Garena Plus if you need from first link.
Then download this:
When you download and instal Garena. Copy executable file which you have downloaded from zip archive, into zero hour folder. Rename this executable file to RA3. Then, launch Garena normal, enter red alert 3 room like before, and before you launch the game make these settings. Executable settings should be pointed to RA3.exe file, and in game boostrap parameters you should write this: target="generals.exe"
It should work!
Credits to www.cnc-contra.com
Edited by dcesarec, 17 February 2013 - 09:39 PM.