Hi There,
 
I'm very new to UCS, and currently tpoc'ing UCSM 2.0(q); so not 100% if this is relevent to you?
 
Here's one possible code snippet for performing this task with 0.9.8 Powertools. (least what I have been able to determine so far)
 
Note: You must trigger the restart via UCSM; otherwise it does not know a restart has occured.......it's a "feature" of the DME/AG/MIT automagic :-)
 
# Loop through each SP requiring acknowledgement
${lsAcks} = Get-UcsLsmaintAck -OperState "waiting-for-user" 
   
foreach (${lsAck} in ${lsAcks})
{
     # perform any activity on host prior to reboot here. i.e. put vmHost into maintenance mode etc.

     # Acknowledge Maintenance Acknowlwedgement to progress reboot
     Set-UcsLsmaintAck -LsmaintAck ${lsAck} -AdminState "trigger-immediate"
    
     # Wait for UCS state change; reboot triggered
     ${lsAck} | Watch-Ucs -Property OperState -SuccessValue pending-next-boot -PollSec 30 -TimeoutSec 600
   
}
 
Hope this helps?
Dave