I wonder by any chance is there a way to install vxworks on vdx86d(vdx6354)? I searched a lot on the net and did not find NO to this question, but no manual or help could be find by me. anybody did this before and know how to do it?
VxWorks certainly runs on PC architecture x86 targets; there is probably already a suitable 80486 BSP that will suit this board. You can search for a suitable BSP here. There is only one BSP explicitly listed for 486 targetted at VxWorks 5.4/Tornado 2.0 - so it is as antique as 486 architecture itself. VxWorks 6.9 however has a single unified BSP for x86 which will no doubt work with your board.
VxWorks is not "installed" as such in the same way as a GPOS such as Linux or Windows; rather you link your application with the VxWorks libraries to create an application image that runs directly on boot. How the bootstrap process works varies between architectures and hardware implementation, but as a generic PC architecture board, booting a VxWorks application on your board will be the same as any other PC target. As such what you need to look for are directions on booting VxWorks on PC architecture rather then being specific about your actual board.
On PC architecture you can boot from mass-storage, or from a network server. Booting via a network connection is the normal method during debug/development. A great deal of the information available is for older versions of VxWorks. However it seems that it is possible to boot VxWorks via a VxWorks specific bootstrap, or from a generic PC bootloader such a s U-Boot.
Ultimately Wind River Support is probably a good starting point.