Is there a way to keep the compose key functional even when I'm using a different language?

I installed the Chinese - Pinyin input method using these guides from Pinyin Joe:

1 - http://www.pinyinjoe.com/linux/ubunt...nese-setup.htm
2 - http://www.pinyinjoe.com/linux/ubunt...in-chewing.htm

I'd like to be able to make diacritics / tone marks (e.g. ǎ, é, ü) without having to switch out of Chinese input or to open the character map, but switching into Chinese input seems to disable the compose key. Any ideas?

Using Natty.