things to check:
1. Project properties -> Build tab. Optimize code should be unchecked
2. Project properties -> Build tab -> Advanced. Debug info should be set to full. See this: http://stackoverflow.com/a/7713781/147530

in .csproj look for following (yes i wanted to debug release build in vs):
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
<DebugType>full</DebugType>
<Optimize>false</Optimize>
<OutputPath>bin</OutputPath>
<DefineConstants>TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
<DebugSymbols>true</DebugSymbols>
</PropertyGroup>