Steps to reproduce:
- start a new presentation, type in a text, mark it, use "insert hyperlink"
- press F1, find "hyperlinks > character formats" or "hyperlinks > editing". 
Both documents suggest to change attribute of all hyperlinks by opening Styles 
and Formatting > Character Styles > right-clicking the "Internet Link" or 
"Visited Internet Link" character style > Modify.
- when following the instructions, you'll find out that there is no such 
character style as "Internet Link" or "Visited Internet Link"

Googling has confirmed to me the documentation says a bullshit and the problem 
has no viable solution except temporary changing styles of all hyperlinks in all 
documents on your Openoffice installation without a chance to save this change 
to the style of your document. Which sucks indeed if you are handed the 
obligatory enterprise template made in Microsoft Office... <insert complaints 
here>.