[AUCTeX] Fold citep

[Rasmus Pank Roulund]

Hey,
I am trying to make citep{z} macros fold as (z). (citep is from Natbib). 
Is this possible to do somehow? I could not find an appropriate way of 
doing so in the manual.
In have defined a line in Tex Fold Macro Spec as "number of argument" 
and "1". The result is that citep{z} is shown as z after folding. This 
is appropriate for citet but I would like to have citep folded as (z).

Is this somehow possible?

Thanks in advance,
Rasmus