BB Device Software :: Email Address Cache Quick List Error - Turn Off Feature?

In the lastest device OS, the email application on the device caches email addresses from emails you have received, so that when you compose a new message these cached email addresses appear in the quick list along with addresses from your Contacts list. I need to know how to turn off this feature or to at least delete some of the cached addresses. Here's the problem. I have a contact in my Contacts list whose name is Thomas. He often goes by Tom, but I don't have Tom in the Contact record for him. He sent me a conference call invitation in which he used the name Tom to set up the conference. The actual email address is from freeconference.com, but his name appears as Tom. Now if I go to write an email to him and start to type Tom, the cached email appears and I end up sending an email to freeconference.com instead of to his real email address. I'm sure this happens with other contacts as well. Since the real email address is masked in the quick pick list, it is very easy to miss this issue and send to the wrong place.