How to add a normal menu to link to a dynamic view with a % argument

I installed signup module. It comes with a view which has a path like "user/%/signups/available". How can I create a normal menu item to this view?

I tried to put "user/%/signups/available" in the path field to create the menu, the system complains "The path 'user/%user/signups/available' is either invalid or you do not have access to it.".

Any help is greatly appreciated.

Thanks in advance!