I have a BC780xlt (yea its old but I got for $150) with ARC780 . Using ARC780,How do I get it to run the IIi system . when I try to put in the System Fleetmap as B1-S3 in box 1 or b2-s4 in box 2 ( in the box says 1 I try to put in S3)it dont take the S only the 3 ?Im In Camen County ,Do I put in all the freqs. or just the South site? Thanks for the help!