WinCC flexible 2004I

I have the following query w.r.t to WinCC flexible 2004 Standard

1)I want to activate the screen when the value of a particular tag exceeds the limit.

2)
a)I wnat to display the temprature on a button,
b)When operator click this button,it should navigate to another screen.

My Touch Screen is OP170B.

With respect to query 1)

Till now i can assign the limit to a tag and generate the message when limit is exceeded,in a alarm view, but cannot navigate to another screen when limit is exceeded.

With respect to query 2)

Till now i know how to do, 2b) but not, 2a).

Thanks for your time
Regards
Manmeet

Re 1:
You can add a function to any tag, including "Go to screen".
As the trigger you can select "change value", "above upper limit" or "below lower limit".

For the tag you can specify fixed or variable limit values.
Let another tag contain the limit value if it must be variable.

Re 2a:
If you overlay a button with an output field, then you will also block it from being clicked.
Try to put the output field above or to the side of the button.