I've dealt with this, and it's not as easy as it seems (Sprint). The Advanced Config Tool vs. 3.3 can only remap the left softkey, and you have to do things goofy to make it work. I think Mighty Mike figured this one out, and my use of the SEARCH function found it, and applied it, and have made posts similar to this several times, but here goes again.
Here is my Home Screen (notice the left softkey)
Here is what I put in the Advanced Config Tool under Key Mapping
Notice I had to put the link for the program for the left softkey in the right softkey link box. Nothing you do will take away the Contacts from coming up when you press the right softkey, and if you don't enter the left softkey link in the right softkey link box, it won't work.
Clear as mud, right?