C Conversion

I am going through and doing a .h to delphi conversion so I an use a 3rd party dll.

I'm trying to figure out how to properly convert the following struct. The problem is that there is a data field after the union.. I'm not exactly sure how to do this in Delphi.

typedef struct
{
      ACSEventHeader_t      eventHeader;
      union
      {
            ACSUnsolicitedEvent            acsUnsolicited;
            ACSConfirmationEvent      acsConfirmation;
            CSTARequestEvent            cstaRequest;
            CSTAUnsolicitedEvent      cstaUnsolicited;
            CSTAConfirmationEvent      cstaConfirmation;
            CSTAEventReport                  cstaEventReport;
      } event;
      char      heap[CSTA_MAX_HEAP];
} CSTAEvent_t;

What I have so far:

type CSTAEvent_t = record
  eventHeader : ACSEventHeader_t;
  case Integer of
    0 : (acsUnsolicited: ACSUnsolicitedEvent);
    1 : (acsConfirmation: ACSConfirmationEvent);
    2 : (cstaRequest: CSTARequestEvent);
    3 : (cstaUnsolicited: CSTAUnsolicitedEvent);
    4 : (cstaConfirmation: CSTAConfirmationEvent);
    5 : (cstaEventReport: CSTAEventReport);
  end;

  //How do I add heap : array[1..CSTA_MAX_HEAP] of char;