I've read previous posts but my problem is either not covered in them or I simply missed it.
How can I, in the Replace field in Sigil, refer to part of the search regex given in the Find field? For example, the text
"theAmerican" should be changed to "the American".
The Search field is easy, "[a-z][A-Z]" but "[a-z] [A-Z]" does not work in the Replace field beacause Sigil replaces the regex text as a literal instead of keeping the lower case and the upper case letters, whatever they are.
I have almost no knowledge of regular expressions, please help me in this.