вот как я это сделал
var macroFilePath = Path.Combine(addinPath, addinName);
var addins = Globals.ThisAddIn.Application.AddIns.Add(macroFilePath);
if (!addins.Installed)
{
addins.Installed = true;
}
var app = Globals.ThisAddIn.Application;
string macroToInvoke = string.Format("{0}!{1}", LibraryName, FunctionName);
Globals.ThisAddIn.Application.Run(macroToInvoke);