Use the test page to view your image, pan and zoom to the initial view that you'd like, then hit 'save specific view'. This will generate a url lke the following:
http://test.htm?FileName=test.xml&BackgroundColor=0&FOV=60&Yaw=180&Pitch=90&Zoom=0.99&XCtr=0.5&YCtr=0.5&ToneMode=2
For a 'perspective' or flat image copy this portion of the url &Zoom=0.99&XCtr=0.5&YCtr=0.5
and append it to the 'args' that you pass into the hdvHost in the html file, for example
args = 'FileName=test.xml&BackgroundColor=0&Zoom=0.99&XCtr=0.5&YCtr=0.5';
For 'cylindrical'or 'spherical' images use this portion of the permalink: &FOV=60&Yaw=180&Pitch=90
There is also a similar description in this post: http://forums.microsoft.com/MSR/ShowPost.aspx?PostID=1762056&SiteID=37
