That lacking official MMS support is a pain in a ***!

My operator reconfigures the settings in HLR when SIM-card is replaced in N900 after it has been in another phone model before.

So, every time someone puts his/her SIM-card to another phone and back to N900, (s)he has to call to the operator so they manually turn the MMS on again. The operator says they do not even have to, but they just like to play nice. They blame Nokia not to provide fixed XML-config-files to the network devices.