>Does nobody know if it's possible to create a library
>.PLB or .FLL by using the Borland C++ 3.1 compiler?
>If it's possible, which switches I have to use?

There's an article at Malcolm Pitcher's site (FoxPro I/O Address) entitled "Using Borland C++ With The FoxPro Library Construction Kit." It specifically refers to C++v3.1 and gives detailed instructions on using it to create FLLs. It also explains why it can't be used to create PLBs.