It's very possible to do. Look at
this thread for an explanation of what to do. You have to create a .dbpro project file and send that to the compiler. You don't use any command line switches to call it.
However, the tricky part is to figure out when the compiler is done doing its thing so that your IDE can launch the .exe file. You do this via the ShellExecuteEx() and the GetExitCodeProcess() Windows API functions. You can also get the current line number the compiler is compiling as well as any error messages it sends by use of memory mapping (MapViewOfFile, or something like that.)
Trust me though, writing a functional IDE isn't as easy as you might think.
I've wasted 1.5 years on mine.
CodeSurge
Version 1.0 finally released! Code your DBP projects in style.
(And save the kittens!)