MS Regedt32 Q

Hello, gurus, I have just bent on a regedit-like soft. Soon, I am stuck by 2 problem:
1. Though RegEnumKey runs very fast, CTreeCtrl::InsertItem is too slow, it is impossible to reach regedit's speedy interaction.
I wonder if there is an API like CEdit::SetHandle so that I can preallocate a mem.
2. Is there an API RegChangeKeyName, otherwise I have to recreate a whole sub-tree when changing a key's name. regedit react so fast, I can not believe it recreate a sub-tree.
thanx a lot ahead, and any idea will be highly appreciated.