We already have this logged as a feature request. Sorry, but no timeframe when to expect it yet.
(Internal ID=312723127)
The only workaround I can currently recommend is using an existing tool for renaming your files, or using a batch script for this, instead of doing it manually.
I am attaching a simple script which can rename files in the folder where it is placed from the following format:
first_second_third.png
to:
first_third_second.png
​
​So for example this file:
Post_Frame0001_Alpha.png
will be renamed to:
Post_Alpha_Frame0001.png
​
This will only work for files consisting of 3 keywords. If there are 2 or 4, it would have to be changed (for example in case of Post_Frane0001_CESSENTIAL_Direct.png).
If you decide to use it, I would definitely advise to experiment with a few files first, and make backups of the original files, just in case.