Changing the ISO CD-ROM in RHEL 5 for Virtual OS Install

[Ryan Golhar]

I'm trying to install a guest OS (RHEL 5) as a fully virtualized system. 
  I have the ISO images for the CDs.  When I create the virtual system, 
I can point to ISO 1 for the CD, but how do I change the virtual CD to 
ISO 2?  I don't see any way to do this.