Totally unsure at the moment. I do not have access to my dev box right now, so I can't test it either.
The problem with using a full URL is that if you add the calendar to your sidebar, that URL has to change... I have plans of looking more into WP as a possible solution for one of my websites, so I might be able to figure out a way to work with permalinks.
EPC Tutorials... We're here to help!
Offering custom integration services. Contact me here
* Not affiliated with EasyPHPCalendar or NashTech Inc.