It seems the script presented at Reloading docset without restarting Xcode no longer works with the latest release 4.4.1 of Xcode.
tell application "Xcode"
load documentation set with path
"~/Library/Developer/Shared/Documentation/DocSets/myDocSet.docset"
end tell
Quitting and then relaunching Xcode are required.
Any idea on how to update the script to avoid quitting and relaunching?