When using the XML file feature of Advanced Installer, we're only given the option to insert a new node/element as a sibling to an existing element -- in which case, our new element is always inserted *after* the existing element.
In some cases though, the element I'm inserting needs to come before the existing element (found via a search), and it doesn't seem that there's a way to do that. (Specifically, I'm using the XML feature to create/modify some MSBuild project files, where the order of elements is quite important.)