Code:
OnHover="Temp=Parent.Input.LocalText
OnPress=('Parent.')##(Temp)##('.visible=true')"
For OnHoverIn you'd have to do it like the above, because you can't directly execute a parameter value in the OnPress. But as Drumstix said, seems like an error prone way to do it if you use it in code where timing matters.
Btw the non-OnHoverIn type concatenation to push variables to OnPress events is used all over ProfitUI, e.g. for the macro buttons on group/raid windows.