send/receive commands from/to bsplayer using c#

[q12q]

I want to send/receive commands from/to bsplayer, using c# environment.
I went in c:\Program Files\Webteh\BSplayerPro\sdk\ folder and I find there 2 files: bsp.h and bsp.pas. I opened the bsp.h file (is a header for old c/c++ language). I read the instructions there:

//To get BSPlayer window handle use:
//bsp_hand=FindWindow("BSPlayer",NULL);
// then you can send messages, for ex. to get current version:
// bsp_ver = SendMessage(bsp_hand,WM_BSP_CMD,BSP_GETVERSION,0);

In my c# program, I wrote:

//Im not sure is correct but im trying
 p_BsPlayer.Handle.ToString(@"bsp_hand=FindWindow(""BSPlayer"",NULL);");

now for the second part...

//how can I write the next line?
//  then you can send messages, for ex. to get current version:
//   bsp_ver = SendMessage(bsp_hand,WM_BSP_CMD,BSP_GETVERSION,0);  <<<this one

thanks.