How to implement SOVA algorithm

Good morning all,

I'm desperate looking up for a proper way to implement SOVA algorithm in my final degree project.

Some time ago I happened to find this solution:

http://nl.mathworks.com/matlabcentral/fileexchange/3801-soft-input-soft-output-viterbi-algorithm

But I still don't know how to implement it (I'm a bit dumb using Matlab)...

Please, could you be so kind to help me? I'd really appreciate it, since I have two months remaining to finish it.

Thank you in advance!