Hi Marcus,
At this time I don't have a good sample for calling a custom Aras form in a non-modal window, however the Tab Forms community project may meet your requirements.
tab-forms - Demonstrates how to display a custom form in a relationship tab.
Using the Tab Forms project as an example, you could display your custom form in a tab on the Part itself. Users could click this "Export BOM" tab, enter their parameters, and navigate to other parts of Aras without losing their input. You can then use the form's contents in your server method, as planned.
Hope this helps!
Eli
Eli Donahue
Aras Labs Software Engineer
