Oculus macro problem

[Tonyx]

I am trying to down Oculus, one of the last 5 man heroics I have to clear.
I am trying to follow the 5xAmber tactic I found here, but I am doing something wrong with the macroes.

For temporal rift I am using:

/cast [nochanneling]Temporal Rift

and I was expeting it to cast temporal rift first time I press the key, then it would continue channeling even if I mash the button.
However, each time I hit the button, it starts channeling again. Not sure if this is an issue (probably doesn't matter) but I'd like to know why it has this behaviour.

I've also tried:

/stopmacro [channeling]
/cast Temporal Rift

and it has the same result.

[Reglar]

Isn't it /cast [nochanneling: Temporal Rift] Temporal Rift