It is available in the LocalizeDictionary class that is in fact called in ResolveLocalizedValue like this:
LocalizeDictionary.Instance.GetLocalizedObject(resourceKey, target, targetCulture)
The key and targetCulture are clear how to be used and the target is the target object (or null in your case). Note, that this goes with the drawback, that no (custom) converter is called and no buffering is used. I'll therefore add a static method that fits your needs.
LocalizeDictionary.Instance.GetLocalizedObject(resourceKey, target, targetCulture)
The key and targetCulture are clear how to be used and the target is the target object (or null in your case). Note, that this goes with the drawback, that no (custom) converter is called and no buffering is used. I'll therefore add a static method that fits your needs.