Here is specially broken librtcom. It segfaults, when tries to show message. rtcom-call-ui restarts automatically, so this is OK.
Replace you librtcom with this and break USSD implementation from nokia, so as not to be annoyed with their messages.

In SVN you can find qussd and ussdd.py, together tey replace nokia's ussd implementation. qussd is reimplementation of ussd-pad in QT. If QT for maemo didn't have silly limitation of 73px push button height, it would even look good.
ussdd.py handles incoming USSD sessions and, if nobody wants to handle them qussd is launched. So it allows to ented USSD queries from phone application too. It also allows to hadle network initiated USSD sessions.

https://garage.maemo.org/plugins/scm...ot=ussd-widget

Now I need to modify ussd-widget to work properly with ussdd.py and package all this stuff.

I would also appreciate, if anybody would suggest a way to calculate, how many users would use this implementation instead nokia's.