Have been researching for 2 days this problem. Read the MS link provided in help - no joy. Main issue is when doing regex replace, if I try to immediately follow the \1 backref with a digit (eg 5), regex thinks that I am trying to use backref \15 (I think) which doesn't exist. I assume there is a very simple way to do this - but since, according to my research, one cannot make named groups in DOPUS' PCRE flavor, cannot get this simple thing to work.
//GOAL: change the 4 to a 5
RENAME REGEXP FINDREP IGNOREEXT PATTERN "(\#CP.)4\#" TO "\15#"
RENAME REGEXP FINDREP IGNOREEXT PATTERN "(CP.)4" TO "\15"
Neither of these work 