Here is what I fond out.

By testing the SC bombs i found out, that they work if you set them to C50 (25). In this case they have a 14 sec delay before they explode. This works offline with every german plane, that can carry them. It also works against ships (skip bombing). There is no need to at high altitude. Online, for me, the only plane that worked the same way as offline, was the Stuka. On the 109B, 110, Ju-88, the bombs won`t work, if you are not higher then, I don`t know exactly 750 m or so, and they also don`t have any delay. They explode on impact, even if they should have a delay of 14 sec. The Bombs on Blenheim work online and offline, they don`t have any delay. I think the bombs on the Br20 also work online and offline, but I`m not sure about it, since I last tested this when the last patch came out.

Ah something I want to add. If you play offline, you can sink a ship with a SC250, online I put all the bombs of a Stuka (1xSC250 4xSC50) in a ship and I couldn`t sink it.

My wonderings about the subject, concerning MP:
http://forum.1cpublishing.eu/showthread.php?t=23483

Offline in FMB the detonator selection is straightforward issue when building the flights.. just select from dropdown menu... The low level and dive detonators work ok.

But MP ... Plane -> select correct plane -> Loadout -> Bombs -> select the correct bomb -> do your settings -> Save on every menu level .. and still it doesn't seem to do anything. No detonation.

as i already suggested, just wait for the next patch.
It is announced that this whole armament screen than should work.

I only play online...the SC500 with the K fuse go off every time in the 110! The Bombs in the Blenheim always go off too.

But my real question is why can I take off 2,000 pounds over weight in a bf110, but I can only carry TWO 500lb bombs in a Blenheim? The wing and outside bomb rack options don't let you load anything ever..no matter how much fuel you take out or empty the bomb bay.

Come on devs..the bombs are modeled just add them to the drop down menu's!! You wonder why nobody fly's British bombers...yet most axis fighters can carry more than the lone bomber.

German over engineering? ;)