Android facebook sdk.setCaption not displaying signature on Sharedialog?

Question

I am sharing a photo using facebook sdk, but the signature is not displayed. Is there a way to show a signature?

SharePhoto photo = new SharePhoto.Builder()
                .setBitmap(photobitmap)
                .setCaption("Photo made by")
                .build();
SharePhotoContent content = new SharePhotoContent.Builder()
                .addPhoto(photo)
                .build();
        ShareApi.share(content, null);
        shareDialog.show(content);