resValue gradle error: Unsupported type “String” in “generated.xml”

I solved adding the resources also in the defaultConfig block. For you it would be something like:

android {
    defaultConfig {
        resValue "string", "RES_FOO", "RES FOO RELEASE"
    }

    buildTypes {
        debug{
            buildConfigField "String", "FOO", "\"FOO DEBUG\""
            resValue "string", "RES_FOO", "RES FOO DEBUG"
        }
        release {
            buildConfigField "String", "FOO", "\"FOO RELEASE\""
            resValue "string", "RES_FOO", "RES FOO RELEASE"
        }
    }
}

Please note that:

• item type must be string and not String
• item name must not contain spaces (as normal resource name)

EDIT:
Since 0.8.3 it should works fine just declaring the resValue in the build type block.