[Plugin: Ajax Event calendar] Programming Problem.

The Calendar Is brilliant it does what it says.
I am trying to find out if there is any easy way to program some points. Anything you program to appear once is brilliant; anything you program to appear regularly is wonderful. If I want an event to appear on the 2nd week of the month that is easy until it hits a 5 week month then it goes out the window, or am I doing something wrong somewhere? I can only go daily weekly or monthly any ideas please