Forward Accessibility Service Inputs to RDP-Connection

Hello,

in our company we developed a App which get's scans from a mobile scanning device (see nimmsta.com). The scans are forwareded to O/S via the Android's Accessibility Service. The reason is that with this solution we do not have to deal with different keyboard-layouts, key-press delays etc.

Now a interested customer has issues when using Paralles for Android to connect to a RDP Client. I also was able to reproduce this issue with our internal setup.
The scans are transmitted to the Parallels App (via the Accessibility Service) when I'm in a native App menu like the settings menu or the connection editing menu. So this workes fine.
As soon as the connection is established and I'm connected to a RDP-Client the scan is no longer transmitted. Our App detects that it cannot use the Accessibility Service to deliver the scanned string.
I've tried setting which seems to have something with inputs to do but could not get it to work.

Is there any more setting or something I've missed I can try to get Parallels to transmit the Accessibility Service to the RDP-Client?

Thanks in advance
Arno Fuchsberger