Christian,

>i want to access a self written plain C dll from within FVP with help from
>christof lange's struct class

Since you wrote the C code why not give it a "dual interface"? One function that uses the struct to call from C/C++ and one function that takes each item of the struct as an argument. It would make calling it from VFP a lot easier. Then in the C code you can more easily move the arguments into the struct and call the existing function.