I'm not sure how this will work in conjunction with aspx and ftp addresses but, it should be fine. It is how these things would normally be done so, worth a shot. To open in main:
To open in a new window:
The thing I am least clear on is if these commands will bring up the save/open prompt or not. Give them a try and see what happens.
Note: The brackets, quotes and parenthesis used in the code are literal, do not remove them when trying this out.