Quick Tutorial:
1. Open your SSBB iso in the trucha signer
2. navigate to the /root folder in located on the first partition.
3. Right click the __update.inf then choose EXTRACT TO FILE. No idea why this step is needed but it avoids an error 6 in the next step so just save this .inf anywhere; you won't be needing it again.
4. Now Right click the __update.inf again and choose REPLACE. Within the prompt, navigate to where you saved ProphSSBB.inf and select it.
5. Should go through and give a success message. Now right click the partition icon and click Trucha sign it! I Signed both partitions for the heck of it, you should too.
6. Don't forget to region frii.
7. Burn.
8. Go boot her up, when prompted let it update FULLY.
9. Enjoy SSBB without the Dual channels or risk of bricking your wii.
Edit: Works for the Ntsc realease on Pal systems, Great little guide by Rodak
http://gbatemp.net/index.php?showtopic=77946&st=0