How to change the signature Algorithm of the keystore of my app

This question is about this issue:

My app gives 'Package file was not signed correctly' error on google play store.

how can I change my siganture key algorithm? i already have a key and it's alias is poiting to that algorithm that gives the package error on 4.2 android devices:

The selected alias "XXXX" uses the "SHA256withRSA" signature algorithm which will likely have issues with Android 4.3 and older.
Certificates that use the "SHA1withRSA" or "MD5withRSA" signature algorithm will provide better compatibility.

I manage to sign my apk via cmd, but i want to change the default build of titanium to avoid doing that every time i send an apk to the store... my apk key uses the SHA256withRSA witch causes the error, how can I change the default algorithm to MD5withRSA to titanium use by default?

thanks in advance.