Ok, I assume your variables look like this:
%peramods name name name
%permods name name
%pertmods name name

Try using this (slightly modified from qwerty's)
Code:
msg $chan !hm Current ingame mods are $&
@ $+ $replace(%paramods,$chr(32),$chr(32) ; @) $&
; % $+ $replace(%parmods,$chr(32),$chr(32) ; %) $&
; + $+ $replace(%partmods,$chr(32),$chr(32) ; +)