What do you do if you wan't to add a button to the page editor default toolbar? I wanted to find out and here is what I found.
Find the page edit buttons:
Core: /sitecore/system/setttings/html editor profiles/rich text default_old/webeditButtons/ (weird that they use default_old but thats what they do - and that took me a while to figure out)
Duplicate an item there and you have a new button. In the datasection on the new item you find 3 options:
Icon - self explanatory
Tooltip - selfexplatory
Here is my result adding a strikeThough button:
Icon field: found an strike through icon in the standard sitecore image library.
Tooltip field: "Strike through"
Regarding calling sitecore functionality. There is only created 2 functions in the js file:
So if you wan't to make something more that that we would have to write new functions for that.
PS: I did this on Sitecore.NET 6.0.0 (rev. 081022) (the nicam demo site)