What level (GL, Inv) does RMS integrate with Great Plains or Solom

My company is considering purchasing Microsoft RMS for a new retail store. At the same time, we are looking into replacing our back end accounting system (currently using ACCPAC Pro, which does not integrate with RMS). We are trying to detemine how tightly integrated RMS is with either Great Plains or Solomon. Specifically, we need to know how RMS updates the Great Plains / Solomon inventory, General Ledger, Sales, customers, and any other information. If there is no strong integration out of the box and we would need to write a custom interface, we may not purchase the accounting system right away, and just write a custom interface between ACCPAC and RMS to get us through.