Bottom line is that only 5.1 is available from the Squeeze (basis of TKL v12.x) repos. 5.5 is in the Wheezy repos (which will be the basis of TKL v13.x). So in the meantime you have the same 3 options I posted above (except replace "Ubuntu 12.04/Precise" with "Debian 7/Wheezy). If I wanted 5.5 personally I'd probably pin it to the Wheezy repo...
Sorry for very slow response...
I must have missed this post...
Bottom line is that only 5.1 is available from the Squeeze (basis of TKL v12.x) repos. 5.5 is in the Wheezy repos (which will be the basis of TKL v13.x). So in the meantime you have the same 3 options I posted above (except replace "Ubuntu 12.04/Precise" with "Debian 7/Wheezy). If I wanted 5.5 personally I'd probably pin it to the Wheezy repo...