ipxe on virtualbox

[NiKiZe]

It mostly seem that you are using pxelinux, which is not iPXE
I don't understand what your question is.

If you want to use iPXE instead of pxelinux then you need to create scripts accordingly - no need to involve pxelinux at all

Virtualbox uses a minimal limited iPXE as it's base, but it's just a standard NBP.
If you want http etc from Virtualbox you first have to load a full featured iPXE