Hi Jason,
The process is a little different (but similar) for 5.x Here is the related info;
Cisco Unified CallManager Features and Services Guide, Release 5.0(2)
Custom Phone Rings
Introducing Custom Phone Rings
Cisco Unified IP Phones ship with two default ring types that are implemented in hardware: Chirp1 and Chirp2. Cisco Unified CallManager also provides a default set of additional phone ring sounds that are implemented in software as pulse code modulation (PCM) files. The PCM files, along with an XML file (named Ringlist.xml) that describes the ring list options that are available at your site, exist in the TFTP directory on each Cisco Unified CallManager server.
You can get a copy of the Ringlist.xml file from the system using the following admin cli "file" commands:
admin:file
file list*
file view*
file search*
file get*
file dump*
file tail*
file delete*
Customizing and Modifying Configuration Files
You can modify configuration files (for example, edit the xml files) and add customized files (for example, custom ring tones, call back tones, phone backgrounds) to the TFTP directory. You can modify files and/or add customized files to the TFTP directory in Cisco Unified Communications Platform Administration, from the TFTP Server File Upload page.
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a008062b707.html
Hope this helps!
Rob