External Invoicing

SUGGESTED

Because we don't want our sales guys messing up inventory but need them to invoice while on the road to keep their truck inventory correct, we have been using invoiceasap for the sales guys but then have been entering another invoice into BW.  I'm new to the company and BW and this seems like way too much duplication work.  Is there a program that works with BW, where we could invoice and then just import the file at the end of the day?  Or does BW have a mobile app?  Thoughts or suggestions appreciated.