Currently, Slide Numbers are not supported in Brainshark.
As a workaround, if you'd like to keep slide numbers it is still possible to manually enter the page numbers in the footer instead of using PowerPoint's slide number system.
If you would like to request this functionality, I recommend visiting our Product Suggestion forum.
To access the Product Suggestion forum, please sign in to your Brainshark account and select "Product Suggestions" from the drop-down menu in the top right corner. This will automatically create an account for you if you don't already have one (and if you do, you will be signed in automatically).
If you need additional assistance, please contact Support.