Change icon in the Coolmenu

Hello,
i'm trying to do a menu item that allow to connect or disconnect the program to a remote server. When it's disconnected the item has an icon and a "Connect" text, and with the same logic when the program is connected the item has another icon and "Disconnect" text. I've changed the text using

menu->ModifyMenu(ID_FILE_CONNECT, MF_BYCOMMAND, ID_FILE_CONNECT, "Disconnect");

and works butfor the bitmap  if i try to use

menu->SetMenuItemBitmaps(ID_FILE_CONNECT, MF_BYCOMMAND, &m_ConnectedBitmap, &m_ConnectedBitmap);

there's no change of the icon of the item.
There's some way to change on fly the icon?

Thanks