Possibly this is Working As Intended, but it seems odd to me that the crossposter tool strips out all LJ-specific formatting codes, even ones that are using valid syntax for the site being crossposted to (e.g., cut tags in the form of <lj-cut>).

Less unexpectedly, this applies to usernames also, even when using the <lj user="x" site="y"> format where y matches the site being crossposted to. If that kind of smart crossposting isn't part of the plan for current crossposter tool functionality (and I have no idea how much work it would be or if there'd be any interest in it beyond my own) that's cool.