We see clients have problems getting this to work, here are instructions:
Enable Vendor Document queuing. Settings are below.
On the vendor add a contact with a preferred method of contact. On the Misc. tab set the order method to be email.
Creat the PO to the vendor and add items needed.
Check the Send now checkbox to queue to be sent in the vendor document queue.
The Send now checkbox does not always stick, this issue is logged with DGI.
Then check the document queue and the POs should be there.
Run the eAgent task to send them. NOTE It creates a separate email for each PO.
Suggest you turn off the feature to queue POs set to email so they will send immediately. Then when you create another PO and check send now it will pop the email window up to email immediately and it sends using your Outlook or other email client.