That dish and the Invacom LNB were not meant to go together.
Some of the enterprising members here wouldn't let that stop them!

But, you'd need to come up with a mechanical mounting solution.
One thing I've done just to test LNBs, is put one on an 18" dish, use the meter with power from a receiver, and while hand-holding it, move it slowly across the sky.
You have to know generally where to aim, of course!
I found it easy to make the $10 meter scream.
To do that with the hot Dish circular polarized satellites, use the 119º LNB (the one on the long straight pipe) or that individual 110º LNB off to the side.
The minute you can get an indication out of your meter, you'll be off to a great start.
But, be sure to search for circular satellites with the meter.
They are spread well across the arc, and are good signposts for knowing where the other birds are located.
If you insist on getting a more suitable dish, here is an interesting thread to read:
McGuyver and his $50 deal on AzsureShine 36" @ 3ABN:
http://www.satelliteguys.us/free-air-fta-discussion/102541-good-place-buy-dish.html#post973266