Problem with Client parallel printer in a Citrix XenApp Session

  Problem with Client parallel printer in a Citrix XenApp Session

Hello,

we have some Wyse V10LE Thinclients in our production environment with Xenapp 5 FP3 with Hotfix Rollup Pack 7 installed.
We are connecting our printers via a loginscript to LPT1: on the client mapping (\\client\LPT1. Now the problem is that our production software sends labels to the directly connected parallel label printer on the client in the same way as you copy a textfile to the LPT1 but it stops after 8 labels. I have also tested this via RDP and here it works fine. 

I have some tests and these are my results:

It works via RDP, so the problem only is if connecting via ICA/HDX.
It works if you connect from a full Windows Workstation so it could be a problem of the ICA/HDX implementation from Wyse.

So are there any suggestions where the solution could be?

Thanks and Best Regards,
Michael