Yoshi, whilst I have no idea of where anything on this subject is written in seforim I am rather stunned at the post itself.
One gives respect to anyone older than oneself and in fact one gives respect to everyone. Respect is based on polite civil behaviour.
Asking what is the punishment for disrepecting a step-parent – the punishment is seeing the distress caused to the biological parent and the family.
Should this question even be asked?. If the question needs to be asked – I am sorry for the situation that caused it to arise.