Koteswara
I am doing an identical process and I agree on Kevn's method. However alternative process that I am trying at my client is the use of SAP Data Service Tools for conversions .
Usually your Approva template is in the format of XMLScripts.Data services can convert the xmlscripts that comes in packages into .txt files.
If you have thousands of SOD Rulsets then you may follow this process . However a word of caution is to validate the custom risk and functions before the use of the tools.
Parag