Sandhya,
Your project is very interesting.
We used nsxml bundled with OpenACS distribution which does not have many XML features, and I think in very near future it may be replaced with something better (tDOM??). http://www.fifthgate.org has good article on using nsxml with AOLServer.
A look at this link ( http://dev.openacs.org/projects/openacs/developers/todo ) suggests that effort is underway to provide support for XML import /export for content repository. You can co-ordinate your work with that, as Glossary, News, WP, ETP all use content repository to store there data.And ETP itself has its version 2.0 shaping up...