as I tried to indicated in one of my previous posts, probably in an ambiguous way: you need to open multiple sessions _in parallel_. One event session _and in parallel to that one_ one command session. Here "session" means: a separate TCP connection to the OWN server.
The OWN Intro does not indicate that it would be possible to alter the type of a session after having chosen a type at the beginning. At least I do read the diagrams on page 8 and 9 this way. And obviously, as you found out, it actually is not possible.
So here you go with an example:
1. Open TCP connection to OWN server, from now on called "#1"
2. #1 receives *#1## (= ACK)
3. #1 send *99*1*## (= chose event session)
4. #1 receives ACK
5. Open another TCP connection to OWN server, from now on called "#2" and _leave #1 open and running in parallel_
6. #2 receives ACK
7. #2 send *99*9*## (= chose command session)
8. #2 receives ACK
9. #2 send some COMMAND (like *1*1*68##)
10. #2 receives ACK
11. #1 receives an event (a OWN STATUS frame) (like *1*1*68##)
In case the directions are unclear: "receive" means "sent by server, received at client"; "send" means "send by client, received by server". So it's from the OWN client's point of view.
NOTE: There are timeouts involved. After a certain amount of inactivity (I think 30 seconds) the server closes a session automatically. To keep a session open, the client can send ACKs on a regular basis.