Dynamically determine File Name for File/FTP Receiver CC

Hello,

I know that it is possible to determine file names dynamically using dynamic attributes.

However can I combine a dynamic attribute and fixed option in the communication channel?

Example:

I want to use a field of the message to be used as first part of the filename and then add a timestamp using the timestamp function in file cc.

What is the easiest way to set the dynamic attribute for a filename in message mapping? Do I have to use an UDF that set the dynamic configuration header?