HELP! How should I change squid.conf for two cache_dir?

Hi,
I'm tring to set up Squid 1.1.8.
I have two disks for cache, and I want to use these.
How should I change squid.conf?

***Two disks...***
/work/cache -> (I want to set up it "cache_swap 800")
/work2/cache -> (I want to set up it "cache_swap 1600")

##### One part of squid.conf
cache_dir /work/cache
cache_dir /work2/cache

cache_swap ??? <----- I don't know how to change.
##### End of part

Thank you very much for your help.

--
Naoya Ito            l94305@ice.nuie.nagoya-u.ac.jp