I was trying the following formula but it doesn't seems to work:
the input I'm getting is the value of the dropdown list, rather than the lookup value.
If I'm putting the the value as constant and not using the dynamic input its working fine.
Please refer to my post here
I'm not sure why technically the dynamic doesn't work, and if this was suggested in the past.
I hope it can be enabled, I think it will give a great flexibility.