If you need to stick with a similar solution for deploying pre configured machines, but not add any additional provisioning tasks, You create a deploy template with OSD only, PXE boot and press F8.
The machine will see that it is not scheduled for provisioning and prompt for provisioning credentials,
Enter these or provisioning user credentials and then pick the task to schedule straight from the OSD list.
You must set up preferred server even if using the core, and still use UNC names for image store.
Hope this helps.