While I don't know anything about ProMinis, I'm sure the answer is yes, but I'm also sure this isn't a good enough reason to use Software serial. I submit that Software Serial is a method of last resort.
You might find the following background notes useful
http://homepages.ihug.com.au/~npyner/Arduino/GUIDE_2BT.pdf
http://homepages.ihug.com.au/~npyner/Arduino/BT_2_WAY.ino