how to use plugin ivm2 ? plgVmOnProductEdit($field,$param,$row, $product_id);

[adhirath]

hi
              i want to add dynamic field into product  with the help of plugin in joomla2.5 vm2
i got this function plgVmOnProductEdit($field,$param,$row, $product_id); with the help of it i can solved plugin query
but how it is work plz help me.....!
http://dev.virtuemart.net/projects/virtuemart/wiki/Product_Plugins