I would like get some help for .NET testing tool related query!

We have a Winforms based .NET application and we use Infragistics Controls v 3.1. Currently we have QTP 6.5 in our organisation, but QTP does supports only Infragistics 2.0

I am looking to know the possibility of using Quick Test Pro 6.51 or 8.0 for .NET winforms testing.

The problem here is not .NET forms, it is the Infragistics Library that QTP
does not support.

Also how about Winrunner for this possibility, this is clearly a 2nd option and can be used only if QTP does not support our requirement. But from the FAQ's i see even Winrunner is not a solution.

So what is the recommened tool regression testing / functional testing .NET winforms applications with 3rd party controls like Infragistics?

Appreciate your response. Thanks in advance!