Hey Guys,
Was just reading this one and I can probably clarify our process.
We do ferment with an ale yeast and then filter bright and re-innoculate with a pilsner yeast (the same strain that we use in our Pilsner in fact).
There are a number of microbiological reasons for doing so - lager yeast is slightly more vigourous, will ferment a bit dryer, etc. We do only add JUST enough to do the job and post bottle conditioning we actually chill every batch to ensure tight compaction of the yeast. This is just our philosophy and ther are plenty of other ways to do it.
And yes, our yeast is stored in Copenhagen and we propagate fresh conditioning yeast every week. (ale yeast about once every 4 weeks).
Anyway, there you go.... (and yes, I guess you could culture up the pils yeast from the bottle, but as someone said here, probably purchase some and you are guaranteed that the yeast is healthy).
Cheers,
Alex (aka LC Chief Brewer)