How to commnicate with a PDA built-in scanner using vb.net smart device?

Question

I am developing an application to run on a PDA. The PDA is running on Windows CE 5.0 and has a barcode scanner integrated. I am using Framework 3.5 VB.Net 2008 smart device project to develop my application. Now, my question is about opening the barcode scanner to read scanned barcodes into my PDA application. I used system.io.ports to open COM1, 2, 3 and I can get them opened but obviously none of theses ports opens up the scanner. Any idea how to open/communicate with the PDA scanner?