Did you talk about VTune Amplifier XE 2011 XE? Or old product VTune Performance Analyzer?
VTune AmplifierXE captures samples with statistical call stack info. It meansifthe callee ran shortly - so there is no sample captured, and no caller info recorded. (In other word, VTune Amplifier XE provides call graphinfo - onlybut only callees are hot functions)
VTune Performance Analyzer's call graph will do FULL instrumentation of your binaries, so function call will not be missed.