Hi,
you are right - no strobe sensor.
Your idea of the setup will work, but it has a disadvantage: If you use the camera's strobe as a trigger, your camera battery will be finished sooner, and also you need to wait longer before you can take the next photo because the internal flash capacitor needs to be recharged before you can fire again.
A possible solution (does ONLY work if the 5050 has a hot shoe -I don't know the camera-, and it is more expensive): Replace the strobe cord of the S&S with a chord that has a Nikonos connector at the end. Buy the Heinrichs Weikamp Oly TTL-Converter for the PT005 housing and replace the housing bulkhead.
http://www.heinrichsweikamp.net/#/en/olympusttl/
http://www.heinrichsweikamp.net/#/en/bulkheads/
I did this for my Olympus 350, works perfect.
If you use the external Converter for the Sea&Sea connector: In TTL you need the pre-flash. The camera triggers the YS60 for a pre flash, the camera gets a feedback and calculates the power output for the final flash, and the converter calculates the power output from the second camera trigger flash. It works, but... for example I found out that the results are better if you blacken the housings flash window in a way that the light from the internal strobe does not reach your subject and leave just a small window where the light will get to the external sensor. Otherwise you have a mix of internal and external strobe lightg which confuses the external sensor. (I have had this setup before but was not pleased with the results, so I sold the sensor and changed to my current setup).
See your camera manual to find out if the Oly can be set to manual flash.
Hope this is more helpful than confusing...
Jock