Don't send invoice attachment to Xero

When we post the invoices through to Xero (everything is working as expected in terms of transferring line by line detail, project codes, cost centre codes etc), but there is always an attachment in Xero which is the Fresh Projects generated invoice.

This means that when we issue invoices (we are sending client the Xero generated invoice), client can see the Xero invoice PLUS the Fresh Projects invoice, unless we delete each Fresh Project invoice attached at the time of sending the email.

it would be easier to manage if we had the option to not send the attachment to Xero at all.