There are some pages in the help of FMGo (at least with icons), there is a doc as well available for FMGo on tech net (community.filemaker.com), -> fmgo13_development.pdf
You could also create Your own (You probably did so for the app' manual) using 'reflector' for perfect screenshots (might be the best option)
And, btw: please play nice... (http://forums.filemaker.com/posts/b78a2ad667)
You can still grab a screenshot using iOS, this is prob the best way and best resolution.
Press Power and Home button at the same time..