IoC / Multiple Implementations

Hello,

I am currently stuck with the following problem: I try to inject a
list of implementations of a certain interface but it seems it does
not work using the straight approach of injecting a
"List<SomeInterface> impls"

Though implementations exist and a list is injected but it's just
empty. Does anyone have a hint where to look here? Maybe I need to
register that list explicitly.

Thanks,
Michael