Posting data to remote server

I have not done any FMP7/8 IWP sites to date, but I am contemplating replacing an existing CDML site with an IWP site. However, there is one functionality that needs to be retained, but which I do not know if it is possible to do with IWP. Unfortunately, it is not a situation where I can just whip up a test file and try it out, hence my coming to the IWP experts here.

The current CDML site registers people for classes, and then, as a final step, pulls the sales data from the database and posts it to

VeriSign, via a simple web form, to complete the payment process. Is it possible to mimic such behavior using IWP? It seems it should be possible, to create a clickable URL on an IWP layout that could forward the user to the VeriSign website and also send along the appropriate sales data from the database or maybe using OpenURL. If this is possible, would the data have to be sent as a GET, or is there a way the data could be sent as a POST?

Thanks in advance for any help/advice received.

William