I just did the 062 test and the HMC Operation Guide was not enough
Failed the test with 61% correct answers, needed 76%
I believe the advanced Power Virtualization on System p5 pdf does the job better. The exam is all about (D)LPAR, VIO and micropartitioning. Just a few question about the HMC itself.
Here is a link to the pdf mentioned.
http://www.redbooks.ibm.com/redbooks/pdfs/sg247940.pdf