Greetings Carlos, you certainly came to the correct place for this question 
vCO is great for this kind of thing.. I had to play around a little before I got something that looked like what you are asking for which is essentially Reboot a host and wait for it to be connected again.
Well, The "Reboot Host" workflow does indeed tell the vCenter API to reboot a host, but it doesn't wait for the host to come back up, it simply completes right away because that's what the API says.. So, we need to introduce a timer to wait a few minutes and give the host a chance to get powered down as part of the reboot. Next we check the connectionState of the host to see if it is "connected" - if not, wait another few minutes and repeat the loop until the host is connected again. See the attached sample workflow. I would recommend a MINIMUM of 3 minutes for the wait time. Test this a few times in your environment to see what works consistently for you and adjust as needed.