Hi Gerd,
what do you mean with "in higher releases"? The function module RFC_REMOTE_FILE has never been defined on ABAP side. It only existed on C/C++ side in the program rfcexec.exe (contained in the classic RFC SDK). It has been removed from the RFC SDK because of security reasons: as rfcexec was present in every R/3 installation, it was kind of difficult to prevent unauthorized access to it. (Not every SAP user should be allowed to read and write files in the R/3 installation directory... And if a sys admin is not careful, he can easily open that door by a misconfiguration of the ACL files.)
One option for you would then be: just write your own "replacement" for rfcexec. You can then limit its functionality, install it only on the host, where files need to be read/written, implement additional security checks (e.g. you could implement it so that only files in one particular directory can be read/written), etc.
And nowadays you are not limited to C/C++: you can also write such a program in Java (using JCo) or in .NET (using NCo).
Or if you are an "ABAP-only" guy and only need to access files on the local application server, you could use the ABAP statement "OPEN DATASET" instead of making a call to RFC_REMOTE_FILE.
Best Regards, Ulrich