Actually BDC has never really been supported by any version of SAP CRM 
. I wrote a program a long time ago to add/remove e-mail addresses, so you can do this via custom code and don't need to use BDC or XIF. I even think coding this via the BOL would be better .
I don't have a CRM system anymore otherwise, I might be able to provide some code examples. I just know the "correct answer" above is not something I would recommend.
Take care,
Stephen