Are you using Automator for this? If so, for the HHMMSS you can either do "?" for each character or * for a string of characters until the _XXXX begins. Found in the DataWatch help of Monarch, the ? in the top right. The note below says it doesn't work with numeric values but I have used it before like my examples.
So you would be looking at something like this:
Also if the date is for yesterday
I hope this helps.