Telerik's Everlive SDK for Windows Phone 7.5 is missing ExecuteAsync and TryExecuteAsync methods, and thus support for await/async calls.

FacadesExtensions.cs

using System.Threading.Tasks;
using Telerik.Everlive.Sdk.Core.Result;

namespace Telerik.Everlive.Sdk.Core.Facades
{
    public static class FacadesExtensions
    {
        public static Task<T> ExecuteAsync<T>(this AsyncFacade<T> facade)
        {
            var tcs = new TaskCompletionSource<T>();
            facade.Execute(result => tcs.TrySetResult(result));
            return tcs.Task;
        }

        public static Task<T> ExecuteAsync<T>(this BaseFacade<T> facade)
        {
            var tcs = new TaskCompletionSource<T>();
            facade.TryExecute(result => HandleResult(tcs, result));
            return tcs.Task;
        }

        public static Task<RequestResult<T>> TryExecuteAsync<T>(this BaseFacade<T> facade)
        {
            var tcs = new TaskCompletionSource<RequestResult<T>>();
            facade.TryExecute(result => tcs.TrySetResult(result));
            return tcs.Task;
        }

        internal static void HandleResult<T>(TaskCompletionSource<T> tcs, RequestResult<T> result)
        {
            if (!result.Success)
            {
                tcs.TrySetException(result.Error);
                return;
            }

            var t1 = (Equals(result.Value, default(T)) ? default(T) : result.Value);
            tcs.TrySetResult(t1);
        }
    }
}