It's better not to use Pinyin to write when studying Chinese
From my point of view, Pinyin is just used for pronouniciation.
I don't think it's a good way for Chinese begginner to write in Pinyin even though he can not recognize Chinese Characters yet.
It's not only difficult for natives to recognize them, but also means slow improvements for those Chinese learners.
Remember one point: It's very difficult for Chinese natives to recognize pinyins of long sentences.
Now that you know the pinyin for some certain word, why not find a Chinese input method software then try to type Chinese characters?
I recomend Microsoft Pinyin Inpu Method, or 搜狗拼音输入法(It's not an advertisement, because I find it useful. Microsoft and 搜狗 doesn't pay me anything for that, :P).
Just a suggestion. Pinyin is not a language, I think. Just like that no man use English phonetic symbol to write, doesn't it?
Although Chinese teachers teach pupils in that way, actually it is not a right and proper way.
That's my opinion.