I hope I have understood your requirements corrently.
I dont have any experience with Nupoint (and as such there may be functions in nupoint that I am unaware of)
If you are after the option to jump to the voicemail box while waiting for the receptionis to answer the phone, you have 2 options I can think of in the 3300
You could use an ACD group and program up the ACD Path Interflow Dialing List. (please hold for the first availabe operator or press 1 to leave a message)
Or you could use the internal VM Multi-Level Auto Attendant (press 1 for to speak to reception, press 2 to leave a message)
then the configuration come down to if you want them going to the mailbox of an extenions or a virtual mailbox associated to the pilot number
You will also have more advanced options in the Prairiefyre products but they are proberly more than you require.
If you are talking about skipping the voicemail box greeting, sorry I dont have an answer.