The 511 does support the VCD format - the problem is that it can only play pressed CD media reliably, not recordable CD-R or CD-RW. In other words, a VCD bought from a shop (http://www.coolvcd.com for example) will play fine, but you won`t be able to get your home-burned VCDs to work.
It`s a limitation of the actual player hardware, not something you can get around with a code or hack.
Mike