Blackberry 8830 WE and straight Talk

I have a blackberry 8830 and wanna cancel my service wit verizon and move to straight talk. If I get a straight talk sim card, and then unlock my blackberry for use with the sim, then can I....

1. Activate the straight talk sevice from the blackberry OR activate the service from the straight talk cell phone AND THEN USE IT WITH THE BLACKBERRY?
2. Use the striaght talk service with the blackberry and continue to top it up from the blackberry.


Thank u for your replies in advance.

straighttalk is CDMA not GSM. There are no SIM cards.