We need to convert a VBA function and its supporting functions to C# on .NET 4.0. This means you need Visual Studio 2010.
The same Excel sheet must work with the new C# add-in exactly in the same way as the same sheet using the VBA function.
It's very easy to create an Excel add-in in C# so I won't expect this to take longer than a day for a C# programmer.
I'm more than happy to provide with the C# wrapper project for the add-in and so the developer would only have to fill-in the gaps.
I'm not building this add-in myself because I haven't got the time and I needed within a week, by August 4.
I also have to build a function in VBA or C# to implement a mathematical algorithm that does some matrix multiplication and a bit more. It has to be used from Excel.
I'd think it'd also take less than a day for any VBA/C# programmer. Same deadline, August 4. The ealier the better.