Hi there,
If you would like to edit the Playbars, or create your own playbars then that can be possible with Adobe Flash Pro.
Please check this link to know how to edit Captivate Playbars: http://blogs.adobe.com/captivate/2010/11/playbars-demystified.html
Before editing the existing playbars, make sure you have a back up of original .fla files.
Thanks.