After you recompiled it, did you reboot so it could load?
How did you attempt to load it after you compiled it?

Did the recompile complete sucessfully?

Does it still work under your previous kernel? You should have the option at boot to choose more than one kernel...

Sorry, I'm a little confused as to the process you used to try to load it... weather you did the 'insmod bcm4400' before you compiled the new one or unloaded the other module before loading the new one... etc.