As far as I have read through researching your question, you can go to the hardware store and purchase am end cap that fits, use gasfitter tape (like a teflon plumbing tape) seal the end.
Before using a propane
appliance, particularly if you have just connected a cylinder to it, check for leaks
using the following method:
1. Make up a dish soap and water solution.
2. Turn the cylinder valve on with the appliance shut off.
3. Spread the soap and water solution over the hose and the connections with a paintbrush.
4. Any leaks
will result in bubbles forming in the solution.
5. If a leak is indicated, shut off the cylinder valve.
6. Don't smoke while checking for leaks
Here is a picture I found in my travels