Ok, according to the product line manager at Mitel the 5324 will require a frimware upgrade for this to work. Good news is that they were able to give me a time frame on this; the bad news is that the time frame is 12- 13 months. The 5324 will never support the wirless handset (this would require a hardware redesign). The 5312 will never support either of the wireless devices.
I guess the model change was simply for marketing purposes as of right now.