Parse custom build rules from Visual Studio C++ project

I am currently working on a project to completely revamp the classic "MakeItSo" tool to generate makefiles from a Visual Studio 2010 solution. I am updating it to work with Visual Studio 2015, but it features a different VCProjectEngine whose API is slightly different.

I am trying to extract the custom build rules for each configuration programmatically:

using Microsoft.VisualStudio.VCProjectEngine;/// <summary>/// Parses one configuration for a custom build rule./// </summary>privatevoid parseCustomBuildRule_Configuration(VCFileConfiguration configuration,string relativePath){// We find the custom build rule for this configuration (if there is one)...IVCRulePropertyStorage rule = configuration.ToolasIVCRulePropertyStorage;if(rule ==null)return;// We will store info about this rule in a CustomBuildRuleInfo_CPP object...CustomBuildRule ruleInfo =newCustomBuildRule();
        ruleInfo.RelativePathToFile= relativePath;// There is a custom build rule, so we parse it...
        ruleInfo.RuleName= rule.GetEvaluatedPropertyValue("Name");string commandLine = rule.GetEvaluatedPropertyValue("CommandLine");
...

Unfortunately, rule.GetEvaluatedPropertyValue("Name") is throwing an exception stating that the property cannot be found. GetUnevaluatedPropertyValue("Name") throws the same error. Even the "CommandLine" property throws an error.

Any ideas how to solve this?