slowness in smtp tls

[John Owens <wl2.20.jowens@spamgourmet.com>]

Hey, I recently switched to a smtp server that does TLS. Here's my
settings: 

   (setq wl-smtp-posting-server "[my.stmp.server]"	
 	wl-smtp-authenticate-type "login" 	
 	wl-smtp-connection-type 'starttls
 	wl-smtp-posting-user "[mylogin]"
 	wl-smtp-posting-port 587)

This is much slower than when I used to not use TLS on an older
server, on the order of 10 seconds for even tiny messages. I just did
one to test (no body, a 3-character subject) and it took 23 seconds.
It immediately says:

Opening STARTTLS connection to `[my.smtp.server]'...done

then waits for a long time before I see:

Sending...done

I'd be obliged to hear any thoughts about (a) how I can speed this up
or (b) how I can go about debugging what's slow. 

It's using the MacPorts-compiled gnutls tools (presumably). 

Ideally, I would send a message and it would do all the sending in the
background while immediately returning control to me, and then only
let me know if there's a problem. Emacs doesn't seem particularly good
at that sort of background processing though.

Thanks -

JDO