Simulating Turing Machine with writing only on non-input fields on read-only Turing machine Can you show me how to simulate Turing Machine with writing only on non-input fields on read-only Turing machine ?   

I tried to do it be using internal states, but it provides me to infinitely many states, what is not allowed.
Any ideas ? 

Edit
I consider standard Turing machines - one leftly-infinite tape.
read-only Turing machine is for me Turing machine such that it can't write on tape.
non-input fields - I mean part of tape where input is given. For example,
abcd#####...., machine can't overwrite abcd but it can overwrite each #.  However, readonly can  only read this tape, so no changes.  

Edit II
I am searching for solution in which we use functions and Myhill-Nerode theorem. Can anyone provide this kind of solution ?
By Single-tape Turing Machines with write-protected input recognize only Regular Languages, a Turing machine that writes only on non-input fields accepts a regular language.

Any regular language can be accepted by a read-only Turing machine: just form a DFA for the regular language, then use that as the finite-state control of the Turing machine and scan the input from left to right.

Chaining those two facts together gives a full proof of the statement.