Serving SSL sites with same lighttpd instance

Hi!

I'm migrating a server from Apache 2 to lighttpd 1.2.8 and I have 
some questions which I'm unable to resolve myself.

First one: I have a website using http and https. At the moment, 
domain.tld is pointing to the IP x.x.x.50, www.domain.tld to .51. 
  SSL is listening on .51:443. I like to achive the same thing 
with lighttpd. Is there any way to get that without duplicating 
the lighttpd.conf and running a second instance of lighttpd?

Second one: I need to protect some directories from direct 
access. With Apache, my config looks like this:

<Directory /www/domain.tld/imstore/>
    Order allow,deny
    Deny from all
    Satisfy All
</Directory>

<Directory /www/domain.tld/imstore/*/_t>
    Order allow,deny
    Allow from all
</Directory>

...

What's the best way to solve that with lighttpd?

Third one: Some hints to how to guess the right amount of 
php-fcgi childrens?

Thanks for any helpful answer in advance.

Regards,
Andreas

P.S: @Jan: Thank you for this great software: Light as a feather, 
easy to use, native fcgi support and no trouble.