No. The Mail Quota Thermometer pop-up text boxes cannot be modified to add links or custom tags. An enhancement request (SPR MCMA7EDKCW) has been submitted to investigate if this content can be customized in a later release. ( Lotus Software KnowledgeBase #1304730 )
*Sigh*
I wish they would drop the part on how to do compact though. It is kind of misleading since the button will only be visible if you have manager access to you email (which might not be the case in some company). I assume that if IBM provide a default option of registering user as editor on their own mail file they would have thought about this “conflict of information”
Or maybe things have been changed in 8/8.5 to allow compact for Editor access ?