So what I come up now without UDF (what is hard to create to me)

SELECT;
 ICASE(;
  EMPTY(GETWORDNUM(TRIM(cur1.cName),1,'.')),SPACE(Cur2.iLen01),;
  ISDIGIT(GETWORDNUM(TRIM(cur1.cName),1,'.')),PADL(GETWORDNUM(TRIM(cur1.cName),1,'.'),Cur2.iLen01,'0'),;
  PADR(GETWORDNUM(TRIM(cur1.cName),1,'.'),Cur2.iLen01));
 +;
 ICASE(;
  EMPTY(GETWORDNUM(TRIM(cur1.cName),2,'.')),SPACE(Cur2.iLen02),;
  ISDIGIT(GETWORDNUM(TRIM(cur1.cName),2,'.')),PADL(GETWORDNUM(TRIM(cur1.cName),2,'.'),Cur2.iLen02,'0'),;
  PADR(GETWORDNUM(TRIM(cur1.cName),2,'.'),Cur2.iLen02));
 +;
 ICASE(;
  EMPTY(GETWORDNUM(TRIM(cur1.cName),3,'.')),SPACE(Cur2.iLen03),;
  ISDIGIT(GETWORDNUM(TRIM(cur1.cName),3,'.')),PADL(GETWORDNUM(TRIM(cur1.cName),3,'.'),Cur2.iLen03,'0'),;
  PADR(GETWORDNUM(TRIM(cur1.cName),3,'.'),Cur2.iLen03));
 AS vVerbindungsSort,;
 +;
 ICASE(;
  EMPTY(GETWORDNUM(TRIM(cur1.cName),4,'.')),SPACE(Cur2.iLen04),;
  ISDIGIT(GETWORDNUM(TRIM(cur1.cName),4,'.')),PADL(GETWORDNUM(TRIM(cur1.cName),4,'.'),Cur2.iLen04,'0'),;
  PADR(GETWORDNUM(TRIM(cur1.cName),4,'.'),Cur2.iLen04));
 AS cSort,;
 cur1.cName AS cNr;
 FROM curSource AS cur1;
 FULL JOIN (;
  SELECT;
   MAX(LEN(GETWORDNUM(TRIM(Cur2_1.cName),1,'.'))) AS iLen01,;
   MAX(LEN(GETWORDNUM(TRIM(Cur2_1.cName),2,'.'))) AS iLen02,;
   MAX(LEN(GETWORDNUM(TRIM(Cur2_1.cName),3,'.'))) AS iLen03,;
   MAX(LEN(GETWORDNUM(TRIM(Cur2_1.cName),4,'.'))) AS iLen04;
   FROM curSource AS Cur2_1;
  ) AS Cur2;
 ON .T.;
 ORDER BY 1

Update:

this is without mixed stuff, but this is out of spec anyway.