sip_session: handle UserCommandError in shortcuts as well

darcs-hash:20090330082824-b2873-ac10c6d468a6bc9f85012204580fc510b38fc870
sip_session: make virtual keypad appear on Ctrl-SPACE for DMTF sending

darcs-hash:20090330082847-b2873-01732e91a6989eb6ad0cd45bef31737206698253