It is much easier to use putty or some other robust terminal, rather than using the java console from the hmc menu. First log onto the hmc as hscroot and run vtmenu:

ssh hscroot@nad0019hmc02
Password:
Last login: Tue Oct 27 14:00:21 2009 from 10.32.12.45^M
hscroot@nad0019hmc02:~> vtmenu

You will see a list of servers to pick from:

 Retrieving name of managed system(s) . . . 

 ----------------------------------------------------------
  Managed Systems:
 ----------------------------------------------------------
   1) dv_505_one
   2) pr_51A_one
   3) pr_570_one
   4) dv_570_one
   5) pr_51A_one
   6) pr_570_two
 
 Enter Number of Managed System.   (q to quit): 6

Next select your partition:

 ----------------------------------------------------------
  Partitions On Managed System:  pr_570_10DEAEA_Prod.
  OS/400 Partitions not listed
 ----------------------------------------------------------
   1)    serveraixp03                        Running
   2)    serveraixp07                        Running
   3)    serverviop01                        Running
   4)    serveraixp04                        Running
   5)    serveraixp06                        Running

 
 Enter Number of Running Partition (q to quit): 4

And finally, you have a console:

    Opening Virtual Terminal On Partition serveraixp04 . . .


 Open in progress

 Open Completed.



AIX Version 5
Copyright IBM Corporation, 1982, 2008.
Console login:

When you are finished use ~. to close the vtmenu session.

If the screen is locked, you can use this command to unlock it and also start up
a session without traversing the menu’s:

rmvterm -m dv_55A_103878H_Dev_viod02 -p nad0019aixd22
mkvterm -m dv_55A_103878H_Dev_viod02 -p nad0019aixd22