Objective-C and C code in unity plugin

Hi !

I am trying to open a webView from my application, I have prepared this function:

UnityPlugin.h:

extern "C" void DisplayWebViewFromPlugin();

UnityPlugin.mm:

extern "C" {
void DisplayWebViewFromPlugin()
{
    CGRect webFrame = CGRectMake(20.0, 250.0, 280.0, 150.0);
    UIWebView *webView = [[UIWebView alloc] initWithFrame:webFrame]; 
    [webView setBackgroundColor:[UIColor whiteColor]]; 
    NSString *urlAddress = @"http://www.google.com"; 
    NSURL *url = [NSURL URLWithString:urlAddress]; 
    NSURLRequest *requestObj = [NSURLRequest requestWithURL:url]; 
    [webView loadRequest:requestObj];
    [[[UIApplication sharedApplication ] keyWindow] addSubview:webView]; 
    [webView release];
}

}

Then I build a libUnityPlugin.a file and put it into assets dir. I also include UnityPlugin.h file into my xCode project, to link the whole project.

NewBehaviorScript.cs :

public class NewBehaviourScript : MonoBehaviour { [DllImport ("__Internal")] private static extern void DisplayWebViewFromPlugin();

void OnGUI () { if (GUI.Button(new Rect (15, 25, 200, 50), "Show Web Viev")) { DisplayWebViewFromPlugin();
}
}

}

Unfortunately it crashes my application while its starting sending EXC_BAD_ACCESS. When I get rid of Objective-C code everything works just fine. What did I miss including this code into my Unity project?