Using group numbers in replace

[JonF]

I have gobs and gobs of files named like "Fred Bear.pst". I want to rename those to "FBear@red.com.pst", where the "red.com.pst" part is constant. So I selected "String Replacement" and wrote a regex:

^(.)(\S*) ([a-z]*)

And a replacement string:

$1$3@red.com.pst

But this does nothing. "Old name is the same as the new name". What am I missing?

[antp]

You should use [A-Za-z], expressions are case-sensitive
And the next name should not include the extension since here it will stop at the "." (as there is no $ at the end, and the "." is not grabbed by the a-z range)