I did something similar with a macro I wrote awhile back. What I ended up doing was writing a batch script that would navigate to the folder and make a file list. And then execute the batch scrip from with the Activate/Launch function in Macro Express. Here is some example batch script:
c:
cd "C:\Desired Folder Location"
dir /b /od > "Text File Name.TXT"
You will want to put that in a test file with a .BAT extension on it. That will then navigate to your folder and dump all the file names into the "Text File Name.TXT" file in the order they were created or modified. You can then use the Process Text File function in Macro Express to load the file names line by line then use the Rename function to make any changes that you need.
PS you can pass variables to batch scripts as well if you add command line paramaters. Variable in batch scripts start with %1 and ascend %2 %3 ect.