yes you are right, in office2007 saving an opened file to pdf is built in.Addon is recquired for office2003.
Shellexecute with option "print" fails always for files other than txt files.
it works only with txt files.

local m.lcfile
m.lcfile=getfile()
&&shellexecute
DECLARE INTEGER ShellExecute IN SHELL32.DLL INTEGER nWinHandle,;
                                            STRING cOperation,;
                                            STRING cFileName,;
                                            STRING cParameters,;
                                            STRING cDirectory,;
                                            INTEGER nShowWindow

result = ShellExecute(0, "print", m.lcfile,"","",1)
if  m.result<=32
messagebox("Fails")
endi

same thing with shellexecute and "edit" verb.