I had the same problem. This is a bit of a hack, but the way I fixed it was to go into the import.php file which is located in the main/top directory of the Buddystream folder, or the buddystream-premium folder.
If you look for this line in import.php
'actionlink' => 'http://www.twitter.com/' . $screenName . '/status/' . $tweet->id
…you can change it to your twitter screen name. E.g., if your twitter screen name is ‘billgates’, then you would change the code to:
'actionlink' => 'http://www.twitter.com/billgates/status/' . $tweet->id
This will fix storing the proper url for all *future* imported tweets.
I put up a page here that should translate really easily from Moveable Type:
http://rocketboom.wikia.com/wiki/Template_hacks
I have played around with WordPress a bit once and have an instal running so if you give me until tomorrow, I think I should be able to whip up a template and post it here. . .
