Fixed accessing XMLElement instances when building the XML

Ignore-this: dee28b0fff695d2c45609b1d668d3537

darcs-hash:20120816161816-b22ec-84d3235a0176411bc8c9270976c62a8c0cbca31d
Fixed invitation transition to normal state after a re-INIVTE cancel

Ignore-this: 479d3ee31fe3a18a3a79dd0f5704ed36

darcs-hash:20120828111142-56b4d-6011872374fff66ae1d2a0843b376f8eb84b8154