Veeqo will allow you to accept backorders from Magento for products that you currently have no physical stock for in your warehouse. That means your real stock of 0 is set correctly in Veeqo, but the item will still be available for purchase on your Magento.
Your backorders will come into Veeqo as Waiting For Stock and therefore sit separately from your Ready To Ship orders, to avoid any confusion.
1. Log into your Magento Admin Panel
2. Go to Catalog>Manage Products
3. Find the product you want to accept backorders for and under the Product Information panel select the Inventory tab
4. Set the inventory settings as follows:
Manage Stock - Yes
Qty - 0
Qty for Item's Status to Become Out of Stock - 0
Backorders (untick Use Config Settings) - Allow Qty Below 0 or Allow Qty Below 0 and Notify Customer
Stock Availability - In Stock
5. Click on Save
Orders for these backorder products will go into Waiting For Stock and once you receive stock, you can simply allocate stock to these orders to make them Ready To Ship.