yes you can.. serproxy is quite nice in a way that it doesn't care who is transmitting or receiving the data.
You just need to make sure that the data you send from the BS is at the same speed specified in the serproxy.cfg configuration file.
if you terminate every line of text with a character 10 (new line) serproxy will happly translate that into a character 0 (needed by flash to read the data in)
somebody needs to write a nice and easy seproxy tutorial... beltraaaannnnn???!!!! if you are reading this...