How to assign an INTERNAL Wifi Adapter to the guest OS in VM?

I'm having trouble assigning my Host Wifi Adapter (which is installed internally in my laptop) DIRECT to the guest OS [Windows XP x86] in the Oracle VirtualBox VM.

I tried so many ways, like Bridging, NAT and etc. But only Bridging sort of worked, but it wasn't a direct assigning, my Host OS [Windows 7 x86] was still able to use WiFi and connect wireless networks, whereas in the guest OS I wasn't able to even see the available wireless networks list.

In several forums I found out the conclusion that only assigning the external WiFi adapters (like USB-Stick) to the Virtual Machines is possible.

Any ideas?

Unfortunately no virtualization software allows for direct access to hardware devices like that.

Compare VirtualBox with VMware Fusion and Parallels for Mac. All 3 of those programs behave the same way. The only devices that can be directly accessed are usb devices. Everything else is abstracted though the virtualization engine. (Though you could argue that the vm has lower level access to cd rom's and storage devices).

I wish I could give you a better answer, than simply to buy a usb wireless card.

Some improvements have been made at the hardware level to support hardware passthrough. For example, Intel has released processors that have advanced virtualization features. You can in theory, connect multiple video cards in your computer, and assign one of the video cards to a Virtual Machine. That VM would then have full control over the graphics card.

Intel calls the technology VT-d
http://software.intel.com/en-us/blogs/2009/06/25/understanding-vt-d-intel-virtualization-technology-for-directed-io

That is not possible if you use inbuilt wifi card. You can buy an USB wifi dongle and enable it in virtual machine. Ensure to have all guest addons. If you expose the USB, you can use it in guest OS.