Thank you Jan for the replay, effectively I make 2 inserts, one in caldav_data and another in calendar_item, using a dav_name composed by some primry and forien keys of a third part app that my tool also manages, so I make some kind of relation. I will try to make it the way you say, but I hope that I can keep choosing the dav_name that I am composing in that case and not be obligated to let the generation of the dave_name to server. As a guideness from your side, would you please indicate me the location in caldavzap code the locations of the rutines/procedure of adding and editing an event so I can use it as an example of and have an idea of how I can perform it from my side when needed (I am not expert in html (PUT, GET) neither ajax, I am a new php programmer and have some knowlages of javascripts and a simple notions o a basic html programming). Thanks a lot.