[c#] How can I call aaApi_CallDefaultWizard to bring up the default wizard in C#?

I'm trying to upload a document to a PW project from a asp.net web application.  I was able to use the API to login.  I'm now trying to use the aaApi_CallDefaultWizard to bring up the wizard to upload a file.

I have declared the function like this:

[DllImport("dmscli.dll", CharSet = CharSet.Unicode)]
        public static extern string aaApi_CallDefaultWizard(IntPtr hWndParent, string lpctstrTitle, int ulCategoryId, int lMessageId, int ulParam1, int ulParam2, IntPtr lplResult);

I'm not sure how to actually call this.  The closest I've seen to an example is this C++ code, but I'm not able to do this in C#.  Not sure how the paramaters are created.  http://communities.bentley.com/products/projectwise/projectwise_programming/f/342995/t/92484.aspx

Is anyone able to point me in the right direction or a C# example please?

Thanks