Search and Replace in OpenOffice Calc

I am currently busy mining through thousands of lines of research data that mostly contain time tags. I imported them into OpenOffice Calc where they have the following format:

05:23:33:97

denoting hours, minutes, seconds and hundredths of seconds. However, even when you define your own time format in the cell properties, OpenOffice refuses to do any calculations unless you change everything to the

05:23:33.97

format. As it’s a very menial and time consuming task to change one period over thousands of lines, there must be a way to have the program do it. Well, I finally found it (using the search function in the OpenOffice forum). Hagar de l’Est brought me on the right track. The solution for my particular problem is:

Search for: (..):(..):(..):(..)
Replace by: $1:$2:$3.$4
In the More Options, check the Regular expressions.
NB: Search in field should be Values.

Now just highlight all the cells with time tags and have the Search and Replace function blast away anything that gets in its way.