Replacing Postfix

[IT geek 31 <itgeek31%googlemail.com@localhost>]

Hi,

I have an excellent Postfix installed and configured exactly how I need it.
The only thing it lacks is TLS and SASL support.

I know I need to remove the package I have, and compile a new one from
pkgsrc.  Unfortunately I have no idea on how to do this.  I have all the the
certificates in place, along with all the relevant files for Postfix
(helo_access, sender_access, main.conf).

Please can someone give me some pointers on how to compile Postfix from
pkgsrc, to include TLS and SASL support?  I need to remove the installed
package (which I can do), and any base install.

Many thanks,