Multipoint bluetooth wont work with iphone 3g

Question

I have a motorola H721 multipoint head set. its a great head set with noise cancellation.. I work outdoors and need all the help i can get...
I have the iphone 3g and a work phone Nokia.. 
my problem is that the iphone will not mulitpoint with the bluetooth. 
it will pair but when i pair it with any other phone the iphone bucktooth goes into twilight zone... the symbol is there but white not blue... now if I un-pair the other cell and re pair the iphone comes back to life.. 
Trust me I tried a lot of combo's.. even used my son's 3g to see if mine was defective.....
We made sure that the iphone was completly turned off before i paired it with the other phone

please help me Fixya, your my only hope. (sorry starwars marathon)