Bin locations and Addon

Hi,

I am developing an addon, this has the responsability of create custom serials but I need set the bin locations for any product created.

my addon has the following fields.

product quantity location

00-11-A 3000 00-A1-23-1

When I see the automatic creation form, you can set the location and this can be asigned. How I can to do its?

If can be hard to understand, how can I to change the variable for any form without focus? or can provide me some tips to do it?