This is my bike mount with the E-10 attached. It is fixed by fabric coated rubber straps (the yellow ones) while the plug at the bottom is fixed with a grey rubber strap (it used to jump out of the E-10 after a while).
The Garmin eTrex is mounted with the standard Garmin bikemount.
This is the bikemount without the E-10. You can see the many holes I made into the plastic to make the hot-glue (that is used to stick the foam to the plastic) get a better grip.
The whole thing seen from below. There is a batterypack mounted (it had some contact problems, hence the wild construction at the contacs) that keeps the E-10 running for a whole afternoon at least.
To mount the stuff to a bike there is a clamp, attached to the bottom plastic plate. The clamp is usually used for "SIGMA"-Bikelamps (a german company), they sell them as spare parts. These things make a really good connection, mine never failed yet, even in roughest conditions.
On that picture you can also see the two level construction of medium hard plastic plates (think its polystyrole) that are attached to each other by a foam that is used for backpack-shoulderstraps. That foam has exactly the right softness to damp hard hits while riding. Its the kind where you can't see the "bubbles" of the foam, a very dense material.