Now that you've updated the max URL length (what is the max length btw?), and allowed POST requests;
There still seems to be a rather short maximum POST variable length. I'm trying to use an android service called "notifymyandroid.com" and the minimum variable length necessary to fire off a message (including API key, event, status and description) is 91 characters. But, in 91 characters, that is an event, status and description using 1 character each.
From what I can tell, your variable limitation is 99 characters.
Here is an example minimum POST data:
Also. a bug: When you save a POST request, then return to the webpage, it reverts back to a GET request (although the post data remains hidden in the POST data field).