Depends on what you mean by IVR. In the truest sense, an IVR is Interactive Voice Response - like calling in and having voice recognition.
I've found over the years that a lot of folks coming into the voice world consider an Auto Attendant (press 1 for this, 2 for that) an IVR.
That said, on the Mitel MiVoice 10.1 platform - there are usually 2 types of voicemail used - either the internal (Embedded Voicemial) or MiCollab (NuPoint Unified Messaging).
And then it depends on the host platform that MiVB 10 is on.
EX or Virtual - you can have the Embedded Voicemail and it has a Call Director Call-Flow similar to that inside the NuPoint. I think this is also on the SMBC controller.
If you're using the Embedded Voicemail on the MXe-III, CX-II platforms, you're limited to the traditional Multi-Level Auto Attendant.
The NuPoint UM Call-Director/Call-Flow is quite simple - starting with "When I receive a call..." Build out the form as simple or as elaborate as you want.
Alternately, an Auto Attendant could be set up in the MiVoice Contact Center (MiCC) with appropriate licensing. I've found that this is very clumsy and not very common.
So, without more info, where exactly are you trying to build out the IVR?