Any experience with Canon DR-2050C or similar?

I'm trying to implement my own silent Twain-Interface for a Canon DR-2050C. I nearly got it, but if I change the "Feeder Settings" in the original Canon-Twain GUI from "Standard" to any of the two other possibilities and afterwards use my own GUI, a smaller Canon-GUI shows up if I scan with my own interface, which I try to avoid.

Does anyone of you have an idea, which capabilities I have to set to make "my" interface silent? I did already set the Indicater-Cap to false and start aquiring with the TwainUserInterfaceFlags.None Flag.

Thanks a lot for any hint!

We are using the DR-9080C, my code looks like the following:

this._twain = new TwainSession();

this._twain.Startup( this, string.Empty, string.Empty, string.Empty, string.Empty, TwainStartupFlags.None );

this._twain.SelectSource( ConfigurationManager.AppSettings["ScannerName"] );

this._twain.EnableDuplexScanning = true;

this._twain.MaximumTransferCount = Convert.ToInt32( ConfigurationManager.AppSettings["MaxImages"] );

this._twain.AcquirePage += new EventHandler<TwainAcquirePageEventArgs>( this.Twain_AcquirePage );

this._twain.Acquire( TwainUserInterfaceFlags.None );

this._twain.AcquirePage -= new EventHandler<TwainAcquirePageEventArgs>( this.Twain_AcquirePage );

And it doesn't show the dialog box for me.

The Twain specification has this paragraph:
=====================================
Note: Some Sources may display the UI even when ShowUI is set to FALSE. An application
can determine whether ShowUI can be set by interrogating the
CAP_UICONTROLLABLE capability.
=====================================

I suggest you check the value of CAP_UICONTROLLABLE to see if this is the case with your Twain driver. If it returns True, I recommend contacting the vendors of your scanner driver to see why they display it.