Macroing Hunter's Mark with Arcane Shot? HELP

I need to know if it's possible to macro HM with another shot.
- I realize HM is on the GCD, I don't need to be told this.
From what I understand it should look something like this:
/cast [if, target, noexists] Hunter's Mark
/cast Arcane Shot
I know this isn't correct. However, if you simply macro /cast HM /cast AS, the result is continuous re-application of HM. Is there any way to macro HM so that it applies the first time, and not again after that on each press?

So now I know this can be done, however with one disadvantage. The macro looks like this:
#showtooltip
/castsequence reset=420 Hunter's Mark, Arcane Shot null
/cast Arcane Shot

This will cast HM then AS, then null the sequence and then continuously cast AS. However, the tooltip no longer shows, and the icon is greyed out, so you cannot see if you have the required focus or not. Almost there, need more help!
bump, edited
Try this instead

/cast Hunter's Mark()
/petattack
If the Arcane Shot tooltip is all you're missing, than your macro should look like:

#showtooltip Arcane Shot
/castsequence reset=420 Hunter's Mark, Arcane Shot, null
/cast Arcane Shot

Couple things I should warn you about this macro. Hunter's Mark is usually applied before a pull, so if a second pull occurs before the macro resets, you won't be able to apply another HM. Secondly, its usually better to simply apply a mark before the tank pulls, as marking after a pull wastes a GCD, which is why I stopped macroing shots or pet attacks with Hunter's Mark a long time ago.

If you're really insistent on marking and attacking simultaneously, then I would do something like:

#showtooltip Hunter's Mark
/cast Hunter's Mark
/cast Petattack
/startattack
He can consider using reset=target instead of a timer so that the macro resets everytime he changes target.

Anyway, seeing reset=420 somehow gives me the feeling the OP has a slight misunderstanding of the reset=xxx conditional lol..

Reset=420 means the macro resets to first ability 420secs after you last pressed the macro.

most Hunter's macro HM with Pet Attack and/or trinkets.

i don't think it is possible to stop applying HM if it is already up. hence, why we macro it with other stuff not on GCD.

Good call. I recently replaced my hunter mark button so I could stop being a clicker. I now must figure out how cast hunter mark and send pet. I want to use mouse5 (right ring finger button).

Try this instead

/cast Hunter's Mark()
/petattack

Wow thanks...Works beautifully with mouse button 5. Click my right ring finger , pet goes in on a marked target.