如何使用greasemonkey脚本使用fogbugz中的Web服务下拉填充文本框？

I want to replace the 'client' field text box in fogbugz when you edit a case to be a drop down instead populated from a separate web service that will keep the client options up to date in our fogbugz. Is this possible? Will the choice they select in the drop down be able to save the same way it would if they had typed it into the text box?I want to replace the 'client' field text box i