Fedora Installation :: F11 - VirtualBox And Kernel Compilation

I'm trying to get a fedora guest running reliable smp under VirtualBox 3.0.6. The VirtualBox manual says "Some Linux distributions, for example Fedora, ship a Linux kernel configured for a timer frequency of 1000Hz. We recommend to recompile the guest kernel and to select a timer frequency of 100Hz." So I tried recompiling the kernel. Being a responsible lad, when it came to setting the kernel specs:

Code:
# Polite request for people who spin their own kernel rpms:
# please modify the "buildid" define in a way that identifies
# that the kernel isn't the stock distribution kernel, for example,
# by setting the define to ".local" or ".bz123456"
#
# % define buildid .local
%define buildid .rim_for_vbox
I've successfully built and installed kernel, headers and firmware:kernel-2.6.30.5-43.rim_for_vbox.fc11.x86_64.rpm
kernel-firmware-2.6.30.5-43.rim_for_vbox.fc11.x86_64.rpm
kernel-headers-2.6.30.5-43.rim_for_vbox.fc11.x86_64.rpm
The system is working fine (well, so far). But trying to install the VirtualBox Guest Additions kernel add-ons still gives me

Please install the build and header files for your current Linux kernel. The current kernel version is 2.6.30.5-43.rim_for_vbox.fc11.x86_64. I'm pretty sure this is because my kernel doesn't match the development packagekernel-devel-2.6.30.5-43.fc11 (x86_64). So the key question is, how on Earth do I create a development package to match the responsibly-renamed kernel?