Pay late a couple times and see how fast it shows up.
Credit reports are used as a collection tool more than anything else. You won't find your cell phone on your credit report either unless you pay late on it or get it charged off. Since it costs money to report to the bureaus you'll find that many companies (power, gas, rent, etc) don't even both reporting unless you go dilenquent on them. It may be that you won't see some accounts on there, but since all small business cards are the responsibility of the cardmember who applied for them, it will get reported on your personal credit report if it gets reported at all. The only type of card that won't hold you personally liable are corporate cards that get issued to you. My AMEX that is issued by my department doesn't show up on my credit report, but my three other AMEX accounts (two of which are business cards) show up. Blue and Plum for business are reporting on my three bureau reports, so don't be surprised if they show up at some point.
I'll do a little research and find out if there are any cards that we don't report as a matter of policy. Well, cards we don't report until they go dilenquent, that is.
I'm sure we'd report anything that could be used as a black mark.