Which type of numbering are you missing? BRC supports /AUTONUMBER
/AUTONUMBER:Start:Increment:Mode:Separator:Base:Pad - this allows you to append an incrementing number to the filename. The parameters are as follows:
Start - the number at which to begin
Increment - how many to increment by each time
Mode - Prefix, Suffix, or Both
Separator - the text to place between the name and the autonumber text. Can be blank.
Base - The base number to use. Normally 10, but can be 2 (binary) to 36. There are also two special bases, 37 and 38, which will cause only letters A-Z to be used.
Pad - you can choose to pad the autonumber. e.g. a pad value of 3 would result in 001, 002, 003, 004 etc.
though it hasn't been updated with some of the recent changes that are in BRU.