ECPG does not recognise typedefs

Postgre Version: 7.3
OS: Linux Mandrake 9.0

In a C-File I have included a header file which globaly defines some typedefs
of variable types like following:
  typedef long MYLONG;

When I write in the file the following definition:
EXEC SQL begin declare section;
  static MYLONG sqlLongHostVar;
EXEC SQL end declare section;

the ecpg precompiler seems not to recognise this type although it is defined
in the included header file. The following error occurs:
ERROR: invalid datatype 'MYLONG'