Change document log in SPECIFICATION MANAGEMENT

Dear Gurus,

I was trying to follow

Creation of Change Documents

Help says run report program RC1_CHANGE_DOCS_LOG_FIELDS_DPL  and then When you have saved the entries, you can display the log for change document creation by choosing Extras -> Change Document Log in the initial screen for specification editing

but change document log is disabled in my menu.

what values i need to maintain for

• CD_PROTOCOL_SAVE_PERIOD
• CD_PROTOCOL_START_DATE
• CD_PROTOCOL_START_TIME
• 
  
• 
  

Thanks in advance.