Venting help second floor toilet and bath

[mromano715]

I am remodeling a home and after removing the ceiling found my second floor bath to have no venting at all. I need to rework the plumbing to add venting and cleanup the horrible mess left by the former owner. My question is this....My second floor toilet is about 12 inches from my soil stack and my floor joists are only 5 1/2" With the Stack next to the toilet and under the second level floor I have no more room to continue the stack up to create my vent. Can I Connect my toilet to a long WYE on its back and use the right Hub to create my vent and the left hub to 90 into the soil stack?

Any help is appreciated

see picture below

 

[Mr_David]

Horizontal vent has to be above the flood rim of the fixture.
This prevents the vent from fouling if/when the system backs up.

System backs up leaving floaters in the horizontal vent.
Water drains out leaving the floaters behind.
They dry out and may eventually block the vent.

 

[Mr_David]

picture? ..........