Trouble in getting incoming/outgoing interface traffic at FreeBSD

[joedson]

Guys, does somebody know
how to solve the following
problem?

I'm trying monitor the
incoming/outgoing traffic
in some interfaces
at FreeBSD (version 8.2)

I tried the following
approach:

Using the Zabbix Agent and
creating an item with key:
net.if.in[<nameOfInterface>,bytes]
and net.if.out[<nameOfInterface>,bytes]

But, instead of this bring
incoming/outgoing traffic
It is bringing the total of bytes
recieved/send by the Interface
since it was up.

How to fix it?

PS: At ubuntu the same
approach works!

Thanks in advance!

[ARA]

You must change "Store value" param from "As is" to "Delta (speed per second)" in item settings.

[joedson]

This works!

Thanks!