Description of problem:
The current installation guide (Revision 2-16) describes how ISO image could be downloaded as below:
$ wget --no-check-certificate --certificate=<Content Certificate>\
However, it's not clear what <Content Certificate> stands for. It'd be better add comment that it is the "Entitlement Certificate" file downloaded from the customer portal in the very previous step.
Please reference the install guide for definition: http://docs.redhat.com/docs/en-US/Red_Hat_Update_Infrastructure/2.0/html/Installation_Guide/chap-Installation_Guide-Introduction.html#sect-Installation_Guide-Architecture-Certificates