I can validate your experiences here. Most of the specialists are not fully aware of what the direct email address is or the MU requirement for referral.

However these office manager may know these and may already activated direct email addresses for these docs.

You can go to PT portal=> Address and do then do a directory of the doctors you are interested by inputting just their names. This is how we found the direct email address of many of the docs we were interested in. One caveat, if this specialist is e-ClinilWorks (EcW) EHR user then their direct address is visible to only other EcW users. It is not available to the outside world.

Alternatively, you can also ask their office managers

Thanks
a_ramiz