Not directly in avast 4.8, this is possible in avast 5.0 (which has been out for a year) and avast 5.1 released at the start of this month.
It is so long since I have used avast 4.8 that I really can't remember any workaround to this issue.
Also avast 4.8 is not long for this earth as support for it is meant to end very soon, no specific date given.