Could you use the numpad keys under fn? For example fn-J is numpad 1 and fn-K is numpad 2.
Edit: You might also use a private.xml private.xml like this with KeyRemap4MacBook:
<?xml version="1.0"?>
<root>
<item>
<name>test</name>
<identifier>test</identifier>
<inputmode_only>CHINESE_SIMPLIFIED, CHINESE_TRADITIONAL</inputmode_only>
<autogen>__KeyToKey__ KeyCode::KEY_0, VK_SHIFT, KeyCode::KEYPAD_0</autogen>
<autogen>__KeyToKey__ KeyCode::KEY_1, VK_SHIFT, KeyCode::KEYPAD_1</autogen>
<autogen>__KeyToKey__ KeyCode::KEY_2, VK_SHIFT, KeyCode::KEYPAD_2</autogen>
<autogen>__KeyToKey__ KeyCode::KEY_3, VK_SHIFT, KeyCode::KEYPAD_3</autogen>
<autogen>__KeyToKey__ KeyCode::KEY_4, VK_SHIFT, KeyCode::KEYPAD_4</autogen>
<autogen>__KeyToKey__ KeyCode::KEY_5, VK_SHIFT, KeyCode::KEYPAD_5</autogen>
<autogen>__KeyToKey__ KeyCode::KEY_6, VK_SHIFT, KeyCode::KEYPAD_6</autogen>
<autogen>__KeyToKey__ KeyCode::KEY_7, VK_SHIFT, KeyCode::KEYPAD_7</autogen>
<autogen>__KeyToKey__ KeyCode::KEY_8, VK_SHIFT, KeyCode::KEYPAD_8</autogen>
<autogen>__KeyToKey__ KeyCode::KEY_9, VK_SHIFT, KeyCode::KEYPAD_9</autogen>
</item>
</root>