The IACS registration process is a two step process and below are links with step by step instructions for registering:
1. Register a Security Official http://www.cms.hhs.gov/IACS/Downloads/IACS_QRG_SO_New_User_Registration_2009_10_28.pdf
2a. Register a User Group Administrator http://www.cms.hhs.gov/IACS/Downloads/IACS_QRG_UGA_New_User_Registration_2009_11_11.pdf
2b. Get the UGA PS&R access http://www.cms.hhs.gov/psrr/downloads/Registration_Tips_Providers.pdf
Skip to the PS&R section of these instructions.
Things they do not necessarily tell you –
1. The security official cannot access the PS&R data which is why you need a UGA
2. Once you have the SO access you then register the UGA
3. The SO will approve the UGA registration and also the UGA PS&R access
4. The UGA and the SO cannot be the same person
