Texting, contact manager and Autocomplete

[jaggy13]

Most contacts autocomplete when I am trying to address a txt, but it seems the users I send to most don't.
Is there a cache limit for autocomplete?
Is there a priority thread I could increase on a few to get them on the list?

I have tried recreating contacts, there doesn't seem to be any ryme or reason to who it works and won't work on.
Thanks in advance for any input.

EDIT**
I founds a few settings in HKCU\Software\Microsoft\Inbox\settings (like deleted,sent and inbox count.)
Thought I found what I was looking for here, HKCU\ControlPanel\PhoneExtendedFunction\CDMA\SMS
Value Name IS637MaxAsciiCharactersRx
Value Data 300.

So far no luck.

[ebbtide]

Make sure in the contact that the number you have for them is listed as "mobile tel" number instead of Work or Home