I checked out your tip and saw that it does not answer my question most accurate. Actually this was not what I wanted to modify.
The thing I meant when talking about modifying the TS artillerie cannon was the explosion image (in TS the projectile explodes like an orcabomb) and the firepower. I should have mentioned that earlier, I apologise for the mess with my posts.
Here is my question in a clearer way :

I changed the firepower of the following weapons in the Rules.ini : 120mmx and Fireballaucher. They work fine in TS without FS but not in TS with FS. So how can I get these firepower modifications working in FS and how can I give the artillerieprojectile its original explosion image and firepower ?