SDWebImage crashes using DownloadImageWithURL()

Hello,

I got this Exception when i try to call DownloadImageWithUrl().

System.InvalidCastException: Unable to cast object of type 'MonoTouch.Foundation.NSObject' to type 'SDWebImage.SDWebImageOperation'. at SDWebImage.SDWebImageManager.DownloadWithURL (MonoTouch.Foundation.NSUrl url, SDWebImageOptions options, SDWebImage.SDWebImageDownloaderProgressHandler progressHandler, SDWebImage.SDWebImageCompletedWithFinishedHandler completedHandler) [0x00000] in :0

Otherwise, the SetImage() method works fine.

Thank you!