How to do calculated discovered item?

[gbs]

I've made a template with one discovery rule and one item prototype.

I'm trying to get how many clients i have on my Motorola WING Access Point (Zebra 7522).

The snmp get has two values, one for 2.4GHz and one for 5GHz.

I want to make a new item in this template to sum those two values.

Today, my key for the values is:
wingStatsDevWlRadioStatNumClients[{#SNMPINDEX}]

Sample of what is happening:
discoveryWingStatsDevWlRadioStatNumClients 0.4.150.134.36.56.20.48.48.45.48.52.45.57.54.45.56 .54.45.50.52.45.51.56.58.82.49 2

discoveryWingStatsDevWlRadioStatNumClients 0.4.150.134.36.56.20.48.48.45.48.52.45.57.54.45.56 .54.45.50.52.45.51.56.58.82.50 0

The one with .49 at the end is the 2.4GHz, the other one (.50) is the 5GHz.

How i can sum them?

[Noobz]

Necro post... Is there a solution to this?
I have several situations where I want to do calculations on discovered item values, or simply create an item which tells me how many of some such item were discovered.
Right now I want to take an average of the PoE output voltages of a switch.