If you already have the LV code, and so know which functions you want to use, then you can open the analysis VI of your choice, and you should be able to view the DLL function prototype by double clicking on the Call Library Function Node.
Note: there may be licensing issues with what you are trying to do. To the best of my understanding, the lvanalys.dll contains *all* of the functions, regardless of whether the toolkit was purchased from NI or not, so you could in effect write your own wrapper VIs.
