I'm trying to combine the following two properties:

	propertyList "generate new key file" $ props
		& cmdProperty "openssl"
			[ "genrsa"
			, "4096"
			, "> " ++ key
			]
			`assume` MadeChange
		& key `File.mode` combineModes [ownerReadMode, ownerWriteMode]

I've tried to use withUmask, without success. Is there a way to do that?
