Can I prepopulate a multiplier field?

I have a multiplier field and of course a multiplier-contents where I have a few fields defined.

FieldID: deltager[###][navn]

The multiplier has been set to show 1 repeat from the beginning, and I would like to prepopulate the 'navn' (name) field of that.
I've tried putting this code:

$form->data['deltager'['1']['navn']] = $user->get( 'name' ) ;

But it doesn't fill in in the first repeat?
Question is, does the repeat exist at all before I do a render html?

Ahaa, brackets placed wrong :-) That made it work, thankyou very much!