3D transforms in UIWebView not captured properly with 'renderInContext'

I am just starting out with Objective-C for iOS. I've created 开发者_运维问答a simple app that lives in a UIWebView, generates imagery based on user input, and needs to allow users to capture and share their creations in an online gallery. I have made a method that captures an image of the UIWebView. I don't have my code in front of me right now, but it's similar to the code in How to take a screenshot programmatically and other sources online, and I'll upload it later if necessary.

The trouble I'm having is that my entire app relies on CSS3 3D transforms within the UIWebView to create the imagery, and when the screenshot is generated, the transforms appear to all be flattened. My understanding was that renderInContext: was supposed to show the UIWebView exactly as it appears to the user, but that is not what's happening. Anyone know why this cold be, or how to get around it?

I've really tried to do my research on this one, and the closest thing I could find was this unanswered question: Gray box on UIWebView Screenshot.