I added Tex on pl.spoj.pl/forum. If You want, You may add it here. Maybe it'll be useful.
Here's how I did it:
BBCode -> The way of use: [ tex ]{TEXT}[ /tex ] // (without spaces)
HTML code -> 
Information line -> Tex: [ tex ]Tex phrase[ /tex ] // (without spaces)
Of course I chose a soft option, You may add it another way. 
