No matter how much you might know about a given subject there are times when you cannot see the answer no matter how much you beat your head against the table.
Yesterday was one of those days for me and I lost several hours that I cannot get back. We are working on getting a build of ERPLink out and during some testing I could not get the .net extension part of the product to work. No matter what I tried I could not get them to work, however a set of the extensions build on my local machine worked without issue. Finally I decided to do a side by side comparison of the assemblies that worked vs. the broken ones. Everything looked the same, both having the same .Net version, references, and so on. However, after closer inspection of the Assembly info the one difference was in the assembly title, where the working set had a title and the non working was cleared. It seems that our Finalbuilder build was clearing out the title (we set other attributes like incremented version) and the title is required by SalesLogix .net Extensions. After getting the build fixed to ensure that title remained the system registered and UI elements showed up as expected in SalesLogix.
So make sure that the title attribute is set accordingly or your SalesLogix .Net Extensions will not be located by the runtime correctly.