Hey mate,
As Vince says, for those missions you mentioned there is no need todo anything about DGen as they are 'static' missions. Just follow th einstall instructions in them. If they don't have any just copy the >mis and .prop files into the following path:
HARD DRIVE>Program Files>IL-2 Sturmovik 1946>Missions>Single Missions>NATIONALITY (e.g "GB" for Britain).
I checked and the site you got them from and they are only single missions, not campaigns. They sound good though, especailly that Scourge of God one so I downloaded it myself.
If you want some easy to install non-DGen campaigns (I have nothing agaisnt DGen, just these ones don't use it) may I immodestly point you in the direction of my own campaigns:
http://mission4today.com/index.php?name=Downloads&file=search&sa=104Just Explore the zip folder, find the readme and folow the instructions.