That was a pain but it is do-able. If you are in story mode, have Luke use the lightsaber to deflect all the shots back until the stormies are gone. If you are in freeplay then just use somebody with a blaster to clobber them. Then fly R2 over to the ledge to get the goodies. There is an activation panel for him that will cause half a bridge to be sent out. The other half of the bridge you build by using the Force on part of the X-Wing. I had some trouble getting R2 over to the ledge as he kept coming up short. Get him right up to the edge of the X-Wing platform before you fly him over.