Sleep modes on the mega128

I am working with a mega128 trying to get it into deep sleep mode.  I have used IDLE
successfully on the classic parts.  That reduces power consumption from ~40ma @ 8mhz to
5ma.  The Power down (SM1 = 1) on the mega part is suppose to shut down all clock
functions other than the watchdog, yet, when I use it, the main oscillator continues to
run and my board draws ~10ma.  Now, there might well be other sources of current drain
on the board, since even IDLE mode should draw less current.

Has anyone used the power down mode?  Does the external crystal oscillator actually
stop?  Is there something special (e.g. CLK fuse settings) that needs to be done other
than setting the SE bit and executing the sleep instruction?  If I fail to enable
interrupts the entire processor is hung, so it does appear to be going into some sort of
sleep mode.

Cheers!

----
Larry Barello
www.barello.net