options of pap and chap??

In windows XP,i use pap or chap(the XP's dial program),it can dialing
successful.
But in lwip,use pap or chap can't  auth.
In lwip,how to select pap or chap?

i do it like this:

void pppInit(void)
{
...
pppSetAuth(PPPAUTHTYPE_ANY, USER, PASSWORD);  //can't working successful
//pppSetAuth(PPPAUTHTYPE_PAP, USER, PASSWORD);//can't working successful
//pppSetAuth(PPPAUTHTYPE_CHAP, USER, PASSWORD);//can't working successful
...
}

#ifndef PAP_SUPPORT
#define PAP_SUPPORT                    1  /*Set for  PAP*/
#endif

#ifndef CHAP_SUPPORT
#define CHAP_SUPPORT                    0      /* Set for CHAP. */
#endif

Do i need  to modify other code for auth?