Hi. I had same problem. Try this code:

char *sStart_pan; // this is a pointer to char array with code of panel
ev = engine_open(NULL);

if (!ev) return 1; // acknex.dll not found

//folder with button images
add_folder("%EXE_DIR%\\DATA\\Btn\\");

...
//Allocation of memory
sStart_pan = new char[strlen("bmap = Start_pan.jpg;\
button (381, 229, btnStart_d.jpg, btnStart_u.jpg, btnStart_u.jpg, meth1, NULL, NULL);\
flags = OVERLAY;")];

//copy code of panel to char array
strcpy(sStart_pan,"bmap = Start_pan.jpg;\
button (381, 229, btnStart_d.jpg, btnStart_u.jpg, btnStart_u.jpg, meth1, NULL, NULL);\
flags = OVERLAY;");

//create a new panel
Start_pan = pan_create(sStart_pan,1);

// make it visible
Start_pan->flags|=VISIBLE;

// wait some frame for visualisation of panel
for (int i=0; i<3; i++) engine_frame();

It's working on my computer.
The buttons is shown and method "meth1" is working.
I'm using MS Visual Studio 2005 and A7 engine (version 7.06.1)

With best regards.