Hi, Mexi. I understand the need to send remittance advice by batch. 

Let me share details about the option being greyed out. 

We have an investigation about this, and the status is still in progress. Currently, our product engineers are implementing a solution. Please get in touch with our Customer Care Support team to add you to the list of affected users and receive updates once it's available. 

You can manually print/save the Bill payment and send it to the customer as a workaround. 

You can also run reports for suppliers' totals to see their balances. 

Please don't hesitate to return to this thread if you have more questions about remittance or any other questions. I'll be here to lend a hand.