Forums Scripts & Popups dynamic variables

Hello all,

I have some problem with this type of variables.
On remote I put :

on *:JOIN:#:{
set %entered [ $+ $nick ] joined
}

I expected to have a variable named :

%entered+nick_name joined

but I got :

%entered$nick joined

Where is the error ? Why mIRC don't replace the identifier $nick with its value ?

Thanks

set %entered [ $+ [ $nick ] ] joined

or

set %entered $+ $nick joined