The K-Beater will not scrape the sides of the bowl down and should never touch the sides. Doing so could cause damage to both the bowl and the attachment.
Either increase the speed slightly, or scrape the mixture down halfway through mixing with a spatula or similar tool.
The creaming beater is an attachment with silicone paddles either side and works much like the K-Beater. If it was not included with your machine it can be purchased from Kenwood Spares for many of our stand mixers.