OpenVG combined with OpenGL ES using EGL

Khronos EGL page mentions right at the end of the page, following use cases where OpenVG and OpenGL ES may be combined via EGL:

"Examples of OpenVG combined with OpenGL ES using EGL

1- OpenVG renders front/back buffer of OpenGL ES application (surface sharing)
2- OpenVG renders to OpenGL ES texture buffer
3- OpenGL ES renders on OpenVG image buffer
4- Share OpenVG objects among multiple OpenVG graphics contexts"

Can anyone help me in getting the use case 2 and use case 3 done with EGL 1.4, OpenVG 1.1 and OpenGL ES 2.0? Does there exist any reference sample code to achieve these use cases? Thanks.