Defining user mailbox SMTP in Exchange 2007

Hi,

I'm already able to create a user mailbox through FIM but I would like to create more than one SMTP for each user. For each user I would like to have, as an example, the smtps: user@fim.local and firstname.lastname@fim.pt.

I know that this info is stored in the attribute "proxyAddresses" within the AD, and I tried to concatenate a string to it but it is a collection...

As anybody done something like this? Can anybody help me?

Thanks