As custom release status icons have not been incorporated into BMIDE, they must be maintained at the client level. Most companies use a combination of TEM and batch scripting to deliver custom status icons.
A better method is to create a custom ICD that controls the delivery during an Over-the-Web (OTW) installation. Teamcenter expert Randy Ellsworth presented on the topic at PLM World 2016 in Orlando, May 16-19, 2016.