Cholen,
You can create an event using the transaction SM62. You can follow the below wiki link to understand how.
http://wiki.scn.sap.com/wiki/display/ABAP/Scheduling+background+job+by+triggering+an+event
As far as passing the variables, instead of using import/export, I would suggest you to use a function group and declare the material as a global variable. You can then use FMs to read and write the material #. This way when you perform a where used list, you will know where the import/export happens.
Thanks,
Vikram.M