xamarin emdk "a scan operation is already in progress"

Hi.

I am trying to use Xamarin EMDK to scan barcodes and to scan documents (passports) with Simulscan.

I have used the code present in Zembra samples.

If I use the "scanner" code, it works well

If I use the "Simulscan" code, it works well

When I try to use them together, I have problems.

I would like, by default, to scan barcodes, then, when the user press a button on the display, scan the document.

There is something I have to do to switch from scanner to simulscan? Do I have to disable scanner before enable simulscan.

A message I see often is "a scan operation is already in progress"

Thanks

Alessandro