In order to add additional functionality and checks to the PBo & PAI of HR infotypes you need to implement enhancement 'PBAS0001' using CMOD (See implementing enhancements, step 2+). Once you have done this you need to go to the function modules EXIT_SAPFP50M_001 & EXIT_SAPFP50M_002 and create the includes within them i.e. ZXPADU01 and ZXPADU02. You can now enhance the functionality of HR infotype PBO and PAI by simply adding code to these includes. See example below:
HR Infotype User exits Include ZXPADU01 for the PBO module Incldue ZXPADU02 for the PAI module *Example code. CASE innnn-infty. "Infotype? WHEN '0001'. "infotype 0001 * Processing code WHEN '0008'. "infotype 0008 * Processing code. * etc. WHEN OTHERS. ENDCASE.