I'm also a e-pm1 new user.
played for few days with Sea&Sea YS110 ( pre alpha ...very old) .and pt-ep06 Olympus housing.
To find a way to safe camera battery i tried the different combination between fill and 1/64 flash on the camera
here's my result:
E-pm1 Setting YS-110 setting result
E-pm1 Flash 1/64 mode manual 1 No good
E-pm1 Flash 1/64 mode manual 2 OK ---- > fast recharge less 1sec. Best setting for battery saving and fast shooting
E-pm1 Flash 1/64 mode TTL no good
E-pm1 Flash Fill mode manual 1 OK ----> Slow recharge more than 3sec. Reliable
E-pm1 Flash Fill mode manual 2 no good
E-pm1 Flash Fill mode TTL OK -----> got green light on Ys110 strobe ( TTL) but unpredictable results: some time under exposed some time over exposed....
i'm still working to find a good setup...but i think i will stick to manual....and coming from Nikonos V i'm used to manual modes...
My book here: