Webmail Branding lost with new DH Web Mail

Prior to new DH Web mail…I was able to Brand web Mail

With old web mail (Squirrel Mail configured through DH panel) I was able to “Brand” a specific web mail logon screen for a customer with a graphics presentation and with their logo.

With new DH Web mail I have lost that capability.

Any thoughts on how I can brand over the DreamHost web mail.
I’m ok with the DH Mail but my customers thought they were hosting through me.