My UM+ works almost perfectly on RAZR V3: the only problem is about displaying the credit expiry date. I can make and receive calls and make and receive sms.
I think things go better with brand new cards than upgrades from UM +423.
The most important news is that now there is no more any message of non-existing number if I call UM+ with the phone swirched off: now there is a strange sound...not the best, but better than before!
The customer care answered my later mail, saying they were applying to solve that problem, then advised me to use the sim menu to make outgoing calls with the 6510. What is annoying, is that I had reported that I wasn't able to make outgoing calls
even with the sim menu...I wonder if they have read my mail carefully...