attaching interior neons?

hi im new here and i have a renault clio. i have just fitted some interior neons and want to fit them under the dash board by the foot pedals and then on the passenger side as well but have been unable to fix them onto the car. i have tried double sided tape and also tire cables to try and hook them onto something but both dont work. does anyone know how i could attach them please??

any help appreciated

cheers jon

the only way to attach them other than those two is to use screws as there should be holes in the lights ready for screws!!