Are you up for weight lifting? Get a 5 gallon container and fill it with rocks, that you can lift and make beleive you are using a pump for water. That will tamp down any soil. How about a tamper? Long handled pole, like a shovel with a 6" square steel added to the bottom.

Here is a link that might be useful: Propagating Perennials

You could "step it" in, or use a tamper, or just cover with mulch and eventually the rain will work the seed onto the soil.