Master/Detail Form - Calculate total from detail to master

[SIZE=14px]Good day. I am a novice with Scriptcase and not a coder. I really need help!

I have a Master form linked to a Detail form. The detail form is used for Invoice line items. I would like to display the total of the Invoice line item amounts on the Master Form.

Here are more details:

Forms
Master Form Name: form_accounting
Details Form Name: form_accounting_inv_items

Database Tables Used
Master Form: accounting
Details Form: accounting_inv_items

The database field in the accounting_inv_items that contains the line item amounts is inv_item_amount

The key field is invoice_id on both database tables.

I want to display the total of all the invoice line items for a specific invoice on the Master Form.

Help will be greatly appreciated![/SIZE]

A invoice requiere some process for it creation. There is an example for a Invoice Master/Detail into SC: samples.
Please open project Samples: the forms are: Form38 y Form38_1
[ATTACH=CONFIG]n76306[/ATTACH] [ATTACH=CONFIG]n76307[/ATTACH]

invoice_master-detail.JPG

invoice_master-detail-2.JPG

Thank you very much for the assistance! That helped me a lot and I got it sorted.