Shortly continuing like this (4)

I believe the answer is:
soon
'shortly' is the definition.
(I know that shortly can be written as soon)
'continuing like this' is the wordplay.
I cannot really see how this works, but
'like this' could be 'so' ('like so') and 'so' is located in the answer.
The remaining letters 'on' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for soon that I've seen before include "In a little while" , "Before long" , "Early; readily" , "In the near future" , "in a minute" .)
