I tryed your solution.
So now I get the known buildcraft bug, and i fixed it with the patch.
Now when i log in with my tekkit 1.1.4 I get the error, You dont have the following mods additional pipes.
This is al obvious.
I think the fix works, but know i have to install aditional pipes on my tekkit 1.1.4 to get on my server.
Isn't there any way to convert the additional pipes to builcraft pipes?
After all thank you very much for the quick fix, and i think i just have to do it without the pipes and hack them in the game.