A. Sure you can. With the present version, you need to convert all the data into metric units, enter into WeldPAD, then convert the final design result to imperial units again. That is all. I may in future add a module to automatically do this.
For the conversions, I use a nifty little on-line converter called 'Uconeer', which may be downloaded from the following link: http://www.katmarsoftware.com/uconeer.htm
Here is an example of designing a bracket from 'Manual of Steel Construction, Volume II, Connections, ASD (9th Edition)/LRFD (1st Edition), AISC: