Intercompany INVOIC Account determination.

Dear experts,

I'm trying to setup INVOIC idoc MM Invoice verification for intercompany billing in the same SAP enviroment.

However once the inbound idoc is created im getting error message "Enter G/L Account" As far as i know you configure accoun determination in transaction "OBCB" but im not getting results with that. Common sense tells me that because i have an associated PO to sales invoice it should be using the account determined in the PO but looks like interco dosnt work like that.

Eny Tips/Help?

Thanks for reading,

Dani.