[whpalmer4]

I don't believe you can currently do the attaching on the iPad, but if you do it on the Mac (making sure to embed the file, not to add a link) you can view the file on the iPad. Send in a feature request with the Contact Omni option under the gear menu in the iPad app. Ken mentioned wanting better support for handing files between OmniFocus and other apps at one point, but more requests will get it more attention.