I have two studio lights, Lencarta 300w/s with brolly and beauty dish. I would like to set up a speedlight Canon 430 II or 580 II behind the subject with blue filter to change the white background. The studio lights are triggered, but how do I link the speedlight? Another trigger is available, but it does not go off. Possibly some change needed on the speedlight or camera 7D ? Any suggestions please.