Can't have several arguments

Hey people,

I'm having some trouble to customize the default Calendar module view.

This is my issue :

I have two content types :
Content type "Task" : Contains a creator / a targeted user (field_task_user)/ a date
Content type "Communcation" : Contains a creator / a targeted user (field_com_user) / a date

I can display all the events on the calendar view, without any problem, just by configuring the "Date(node)" argument.

BUT,
I want every people to have his own calendar, so he cans see tasks where he is mentioned, and Communication where he is mentioned.

So i created two relations on : field_task_user and field_com_user

Next, i have added two arguments : User UID, with those two diferents relations below.

When i go see my view with 1 argument : http://www.blabla.com/calendar/3,
it works and i see every tasks where user 3 is mentioned.

But when I go to : http://www.blabla.com/calendar/3/3,

The calendar is totally empty :(

What could cause the issue ? Someone have an idea ?

Thanks,
Max