Service account opening a browser

[Hobbes80]

I have an executable that uses HTTP FORM post commands to open a browser window and establish an SSL VPN tunnel for an application on my XP Pro system (SP2). When initiated by the user logged on to the computer (either via the registry or as a scheduled task using the credentials of the logged in user only) the application runs flawlessly. I can even run the application off of the desktop and it opens up. When I set the service to call the application, the application errors out at the point where it would open the browser window.

From what I have learned, it seems as if there is either a security option that is forbidding the service account form launching a browser in the user's account, or IE is forbidding it. I cannot set the service to "interact with desktop" on the Local System account because it requires access to the file structure (it's backup software) so I need to use a full on user account with admin/logon as service privledges. I have tried altering the registry key to "Allow Interact with Desktop", I found an information file here:
http://www.codeproject.com/csharp/Cs...iceDesktop.asp
that suggested it might fix the problem. It has not.

Any ideas would be greatly appreciated. This is so close to being able to work and it would stink to have it blow up this close.
Regards,
--hobbes

[Hobbes80]

Update:
I've been using the RunAs command to run the application script that opens the web browser. The downside is that it asks for authentication. I downloaded a program called CPAU that encrypts the authentication and uses that with the runas command (basically) so that I don't have to put clear text passwords on a machine.
However, this only works if a browser was opened before the call the script is made and even then, something doesn't work right with the tunnel and it does not allow the connection to be made through it.
GRRR... MS sucks.
Any ideas?