I've created a custom oem.tgz file that works with Varazir's custom installation script. I have attached it to this post. Thanks to Dave for explaining how to do this.
The attached Areca-100202-oem.tgz file uses the latest Areca driver you can get from here: ftp://ftp.areca.com.tw/RaidCards/AP_Dri ... 100202.zip
I've created a USB stick and an ISO file that will list my Areca RAID array as a disk I can install VMware ESXi 4.0 Update 1 to. These were made on Ubuntu 10.04 if anyone is curious about compatibility for Varazir's script and ESXi 4.0 Update 1.