I'm creating an installer source file, and I was wondering if there was any way to check if a file exists on the iPhone/iPod touch through the install script?

The http://iphone.nullriver.com/beta/ site is outdated, but I know of the following commands:
If/IfNot
FirmwareVersionIs
InstalledPackage
AbortOperation
Exec
Notice
Confirm
CopyPath
RemovePath

so is there a list on some other site?

The only one I need is a FileExists or something but can't find documentation.

Thanks