Try visual-paradigm.com for their community edition. You need to put the sequence/collab diagrams into seperate projects as it only supports one diagram of each type per project but it works well and provides the image export required for part II submission.
posted 14 years ago
You can probably also use a trial version of software like Enterprise Architect, which I think is more stable and intuitive than some of the other products mentioned. IMHO only. Regards,