Call of Transaction V-41 with passing the material number to it?!

[Freistedt,Andreas]

Dear all,
 
I want to define a new method in my business object (copy of BUS1001), where
I want to call the transaction V-41 and I want to pass my material number as
a paramter to the transaction. The F1-help in the table of 'V-41' shows me
the paramter id 'MAT', but when I use the coding
 
set parameter id 'MAT' field object-key-material.
call transaction 'V-41'.
 
there is no material number displayed in the transaction.
 
How do I have to change my coding?
 
Best regards,
  Andreas Freistedt
 
Andreas Freistedt
Leitung CC Business Intelligence
Montblanc-Simplo GmbH
phone: +49-40-84001-767
fax: +49-40-84001-95-767
mail to: A.Freistedt at montblanc.de