In Blender version 2.64a, the Collada exporter changed the way it exports material names. All special characters in the material name are replaced with underscores. Before 2.64a special characters like '@' '[', etc. were preserved.
I am using a naming convention with special characters to get addtional material user data in the exported Collada file. But now this doesn't work since the special characters are removed.
Is this a bug I should report? If so, where do I do that? Is there another alternative for getting material user data exported to Collada?
It appears the issue isn't specific to special characters. The 2.64 Collada exporter appears to be copying the material ID name as the material name, instead of preserving the material name.
Exporting a material named "TestMatName[extra]" to Collada produces the following:
<material id="TestMatName_extra_-material" name="TestMatName[extra]">
<material id="TestMatName_extra_-material" name="TestMatName_extra_-material">
I have submitted a bug here: http://projects.blender.org/tracker/index.php?func=detail&aid=33168&group_id=9&atid=498