Question re attaching remote trigger to cold shoe on RB67

I want to set up my RB67 so that I can fire my flash off camera. I have the Photix transmitter and receivers together with two Nikon SB800s. Using a PC cord I have been able to use the trigger to fire the flash off camera. What I would like to do is insert the trigger into the cold shoe on the side of the RB67. However, the shoe of the trigger is a little too wide to fit into the cold shoe slot. Is there any kind of adapter I can get that will allow me to attach the trigger to the side of the body?

Your cold shoe may just be stiff - many of them will have never been used.