It certainly does work online, just be sure YOU are the host. Don't know if your the host? well try this:
Step 1. Navigate to your Blacksops config file (Mostly C:\Program Files\Steam\steamapps\common\call of duty black ops\players)
Step 2. Openup a file called config.cfg
Step 3. Add this text totally down in your config:
Step 4. Save the file and change it's type to read only
seta con_miniconlines "10"
seta con_disable "0"
bind F8 "status"
bind F9 "con_minicon 0"
bind F10 "con_minicon 1"
Step 5. Open the game and join a lobby, press F10 followed by F8 (only have to press F10 once to enable "console" for the rest of the game) and you will see in your left corner text wich displays how much people there are and wich slot you have.
Anyway, awsome trainer I love the gui (probably the reason I only use this trainer >.<) and I hope you will keep up the good work