Webber grill conversion propane/CNG

Maybe someone has the answer I'm looking for. I purchased a Webber grill two years ago to run off natural gas from the house. Used is five or six times, sold house and grill went to storage. New house has propane connect on porch so I figured I could convert grill from natural gas to propane. Everyone/place that I have talked to has said I am SOL, can not convert.



Any ideas?