I would just like to state that as of RC4, as per Lyle above, this is the solution to the problem of downloads not appearing in the user's queue. I would suggest adding this as a default configuration in the uc_file module, but I know, being so close to release 1.0, that breaks all sorts of rules

For those that follow behind, here are the exact steps (you must use the admin interface):

1. Select Administer >> Site building >> Workflow-ng
2. Click "Add a new configuration"
3. Fill in the form:
   • Event: "Customer completes checkout"
   • Label: "Update order status to 'Completed'"
   • Check the "active" configuration box
4. Click "Add a condition
5. Select Payment >> Check the order balance
6. Click "Add"
7. On the editing form, select "Balance is equal to $0.00"
8. Click "Submit"
9. Click "Add an action"
10. Select "Update the order status"
11. Click "Add"
12. Chance the Order Status selection box to "Completed"
13. Click "Submit"

Viola! If you're working on a live site, you might want to leave the "active" box unchecked in Step 3 until you've completed the rule addition. You can always go back and make it active by "editing" the rule from the Workflow-ng "home" page.