I want to say the lower-right character is 德 (virtue), and a look at [www.zhaozi.cn] confirms that it can be written that way (the lower part looks like 亞 and not 心). So that leaves just one character.
Edit: So I'm guessing 宣德孝 is a name, probably the artisan who made the thing. The last character is probably something with the meaning of "made it" or "maker", or maybe a reference to the place it was made, so "Syun Dak-haau (Mandarin Xuan Dexiao) made it" is my best guess as to what it means.
Edit: So I'm guessing 宣德孝 is a name, probably the artisan who made the thing. The last character is probably something with the meaning of "made it" or "maker", or maybe a reference to the place it was made, so "Syun Dak-haau (Mandarin Xuan Dexiao) made it" is my best guess as to what it means.