task.scene

You need to set the correct template for the 1byte register/address. Then the client/you can change its values inside scenes too.

already set to "mode"

the scene page unable to adjust/select the value. please advise, thanks a lot

Hmm seems like it doesnt work. Another way is to make boolean switches for every mode - then add them to the scene/calendar 
 

I posted the wrong picture.

But heres how I've done it. For every mode you need to make a Boolean button (away, home, guests) Then make programs for them, trigger will be the same boolean mode button.

Then these buttons you can add to the scene. client then disables/enable the one they want to use on that scene. 
Somehow you cant add same 1byte value two times even if its value is different. I think thats a bug as it still opens in the scene window´, so you should be able to change its value in there but it wont let me. 

Easiest way is to add Mode to node. Works in calendars and in scenes.

Under Value you can say that 1 means Low, 2 means Hi or something like that.