Aperture: how to rotate less than 90 degrees while cropping?

Hello.

I recently switched form Lightroom to Aperture, where rotating an image (or actually the cropping area) a few degrees while cropping it was very easy to do.

How can this be done in Aperture?  I know how to do the full 90 deg. rotate, but isn't there any other way of just adjusting it slightly when cropping?

I looked in the help section, but cannot find any other mention than the 90 deg rotate

Thanks in advance.

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Andrzej
http://lowflyingbananas.zenfolio.com/