RS-232c hardware device dll provided but I dont konw how to code it with VB.net, possible dll wrapper or possible new dll created

I have a hardware device that comes with a test application as well as the .dll interface however I cannot add the .dll as a referance to my VB.Net Project. I can however declare the functions in my application and have some interaction with the device but the .dll functions have pointers and I am unable to retreive the return values in VB.net. What I need is a VB.Net project that implements all the 21 functions of the provided .dll and will display the results, errors. This may be as simple as creating the wrapper for the .dll or as complex as rewriting/creating a new [login to view URL] using the documentation provided. I am including in the zip file all the .dll's required to run the ECDM-Based test application as well as the documentation needed to code the solution. Please take a look at the attached ECDM-Based application to better your understand what I need to interface with. Project must be done in VB.Net and be well documented.