Please clarify what type of Miscellaneous Statement you might want.

Do you just want to attach some verbiage to explain something on the 1120?

Do you want to show more detail on some specific input for the 1120? 

I want to attach some vierbage on a line on the 1120

Lacerte has a section called "Notes" that would accommodate what you are probably looking for. The only options I see in PCT are a short description with the line number you are referring to OR e-file > upper right is e-file Attachments > Create a pdf attachment and link it to the 1120.