Bugzilla + Command or Script to add text to parameter 'shutdownhtml' in param file

I am looking for One Line Command or a simple script to set the 'shutdownhtml' in /var/www/html/bugzilla/data/param file.

From...

       'shutdownhtml' => '',

To....

       'shutdownhtml' => 'Archiving DB and Bugzilla config... It could takes 5 min or longer.',

Did try to use "sed" but somehow the config above has Single Open quote ' , so seem like "sed" not able to do this... ??

Thanks for helping.

Solution

Thanks to Thorsten Schöning. A solution has provided by him.

sed --regexp-extended 's/(.)shutdownhtml\1(\s+)=>(\s+)\1{2},/\1shutdownhtml\1\2=>\3\1someText\1,/' params > params.shutdown