If your Purchase invoices are not sending to Xero, it is most likely that you have not selected a Direct Cost account in Xero to send the purchase invoices too.
To nominate a Direct Cost account please go to your EMAC account Tab and select the Direct Cost accounts.
1. From the header select the icon.
2. Select the Xero Add-On Tab.
3. Proceed to Step 5. Connect your Direct Cost account.
4. Select the Save button.