LP 9 to LP X: Environment AU stereo/mono problem

(specs listed below)

When loading Logic Pro 9 songs in Logic Pro X, the complete environment is changed to somewhat "mono".

I’m not able to describe the issue good enough in english, so I’ll attach two screenshots which might help.

In LP 9 the "Return 1/Return 2" which I used as "Bus 1-2" was a stereo fader in which the "Return 2" was controlled by the "Stereo-Objekt Bus 1-2", as written there, functional was only the fader "Return 1" in stereo mode.

The other faders were constructed this way, "Return 3/Return 4" were used as "Bus 3-4" and so on.

Everything worked fine.

Now, I opened (Cmd-O) this songs in LP X.

The whole structure ist completely different and ALL faders are in mono mode, and all the Logic AU plug-ins (Delay, Reverb ...) were de-installed.

The mix sounds terrible.

What should I do to get back to the "stereo" versions of my "Return" or "Bus" faders?

Thanks!

LOGIC PRO X 10.2.0 (german version)

Mac OS 10.10.5 Yosemite (german version)

Mac mini (late 2012), 2,6 GHz Intel Core i7, 16 GB 1600 MHz DDR3, Fusion Drive 1 TB APPLE SSD SM128E, Intel HD Graphics 4000

No additional sound card