Thanks for getting back to me so quickly.
First of all, I agree with you. I mean Astah SysML should have the same ability for the Sequence diagram that Astah Professional does, and more than anything, it should comply with SysML specifications correctly.
I didn't mean to ask you to purchase Astah Professional. I was going to offer a free license of Astah Professional until our team updates Astah SysML with the ability.
A lot of our customers would start with Astah Professional, so I thought you might have checked out Astah Professional before you touched Astah SysML.
Regarding the package diagrams, we'd like you to create it using BDD. This is noted on FAQ but should have been more clear. Sorry about that.
Most of our dev. team resource is spent on our flagship product - Astah Professional, therefore updating Astah SysML edition has gone behind we're afraid. If you are happy with the features of the sequence diagram in Astah Professional, I'd be happy to provide a free license for it, so please let me know. (although the duration constraint behaviour is same in both editions..)
So are you currently evaluating SysML tools?