Please let me just take you around the globe with examples...
This company uses the EXISTING Gasoline injectors for conversion to gaseous LPG..
Here is a car to buy that uses both Gasoline and Gaseous LPG... (Same Injectors)
here are kits if you like swapping injectors:
So, In conclusion, once again, I'm saying we need to develop NOTHING for the injector to do Direct injection into a petrol engine. It has been DONE...over and over.