I have a success report :)

Inspite, I am sure I loaded from CD, I tried tge alternative model provided by Geit to hold the ALT key, and then select the CD symbol (appearing next to OSX HDD and MOS HDD)

For some reason this appeared to work better, I got the Update option showing on the installation overlay window

Thanks everyone, hope this will be helping others in my situation too

BR/Tomas