panBy in action is continuous, not single

Hi,
i need to adjust my map , and i call an action to move 45 pxl up, but this action result on a continuous moving up,
how to trigger only one single time ?

<action name="map_45pxl_up">
plugin[maps].panby(0, 45);
</action>

i've tried to call just after :

plugin[maps].panby(0, 0);

but the map continuous moving up.

what the way to do that

thanks

z