No bacteria strains? Sorry to hear that, I'd think they could at least order them from Wyeast of White Labs.
I've sour mashed a half dozen times, with success. IMHO the best way is to mash, cool the entire mash to around 100-120 and pitch in some raw grain, hold at 100ish for 24-48 hours, depending upon how sour you like your beer, then sparge and boil as you usually would to kill the bugs and fix the sourness. 50/50 barley and wheat, sour mashed as I mentioned, and boiled and hopped to 5-10 IBUs makes a great Berliner Weisse. You can always add fruit later in primary/secondary too.