Dry stone walls

Hi 

I want to grow clematis up and along a dry stone wall which is 3ft 6ins high. The cats in the village use our garden walls as a 'cat run', they dont just pass through unfortunately!  I have managed in several places to stop them by strategically planting spikey plants however this particular section of wall doesnt lend itself to tall plants. 

My question is has anyone else grown climbers up a dry stone wall and if so how do you get them to attach to the wall? Or has anyone any suggestions of how i might achieve this.