[Lizard]

Not automatically. However, we use something like the following internally:

set BugURL to "http://bogusBugServer.com/"
tell front window of application "OmniPlan"
	set MyTasks to selected tasks
	set FirstTask to item 1 of MyTasks
	set MyData to custom data of FirstTask
	
	set MyBugID to missing value
	try
		set MyBugID to |bug id| of MyData
	end try
	if MyBugID is not missing value then
		set BugURL to BugURL & MyBugID
	end if
	BugURL
end tell

tell application "OmniWeb"
	GetURL BugURL
end tell

In this example, you put the bug/issue id in a custom column named "bug id", and put the script in OmniPlan's toolbar. Then when you want to view the issue in the web browser, just select the task and click the toolbar button. (Obviously, you'll need to tweak it so it's creating the URLs the way you need them. And you can change the column from |bug id| to something else too.