Open Office and regular expressions

For the first time in my life, I tried to use Open Office for more than 15 minutes. While converting data from an HTML page into a chart I noticed that regular expressions don't seem to work in the Replace part of the Find/Replace dialog.

This must be a joke. My problem is trivial: Convert "8.1 k" into "8100" and "9k into 9000". I can't do it the straightforward way with 2 regular expressions. On an ideological level I'm a big supporter of Open Office, but today all I see is that it's wasting my time. (The corresponding online help for the dialog is not very useful either.)