no concert pitch button

Just enter it as one instrument and then change the instrument (right-click on an empty bit of any measure and choose Stave Properties).

Or, create a score with two instruments, enter the notes in the violin stave and then copy them (maybe a few measures at a time) to the clarinet stave - I like this way as it hones my transposing skills and I like to think I'm playing several instruments well (at least, in my head). Coming originally from British Brass Band music I was self-taught in transposition from about age 9 but it's a skill that benefits from repetition. The added advantage of using two staves is that it is easier to correct mistakes - I know that I can't enter a whole score without making mistakes.