Opening file:\\ url from IWP

I have an application that stores UNC paths to executables in a table. I use the open URL script step so that when a user click a button it executes the program at that path. In the client application, the button works fine; however in IWP, the URL is concatenated with HTTP: so that the resulting URL is HTTP://FILE://xxxxxx/xxx/xxx/xxxx.exe. I cannot seem to find the work around for this. If I manually remove the http: from the address bar and hit go, the link works as expected and the program executes. Does anyone have any ideas? Thanks in advance!