Are you talking about code completion? I wrote a jdeTips article that details everyting if you have access to that or I think you can request a free copy. If not, in general:
1. don't launch Visual Studio from OMW
2. Create a make file project in Visual Studio
3. Name the project what ever you want, I keep several around. Sales Order, Purchase Order, etc. Or just create new ones as needed
4. In the project wizard blank out the default myprojectname.exe, set Include Search Path = C:\e900\system\include;C:\e900\DV900\include (adjust for your actual E1 install path)
5. Add in the BSFN source files (.h and .c) you wish to edit by right clicking "Header Files" and "Source Files" in the solution explorer pane and then select "Add|Existing Item...". See attached for what VS Solution Explorer pane should look like.
6. Optionally in the solution properties set the debug command line to C:\e900\system\bin32\activConsole.exe. This allows you to launch E1 from VS for debugging instead of having to attach to process.
7. Any new BSFNs you wish to edit can be added by repeating step 5.
VS will create browse info by dynamically parsing any source and header files you add to the solution as well as parsing any files specified with an #include directive and any #include those files may have. Since every BSFN has #include <jde.h> for example, this gets all the JDE api calls and definitions.
Just keep VS and your project open. Do check in/out, BSFN build, etc. from OMW but just do all your code edits and debugging in the VS project and enjoy all the wonders of IntelliSense (code completion, etc.). Honestly, I couldn't code w/o doing this.