Must be an easier way to do this?

Question

I am trying to create a password based on the following (very simple) algorithym.
Take the userid("poo"). Convert to uppercase("POO"). Get the ascii value for each character and take the last character of the ascii value to build the password. E.G.
Char ASCII PASSWORD
P 80 0
O 79 09
O 79 099 - The finished password("0"+"9"+"9")
Here is my(i think over complicated) function. I am v new to java so please be gentle with your critiscm :-)
public String MakeUserPwd(String userId){
    String password;
    String charVal;
    int count, intCharCode;
    password = "";
    count = userId.length();
    //For each caracter get ascii val and get last "character" of ascii val to build password
    for (int i = 0; i < count;i++){
      intCharCode = userId.charAt(i);
      charVal = Integer.toString(intCharCode);
      password = password + charVal.substring(charVal.length()-1,charVal.length());
    return password;
  }

Answer 1

for (int i = 0; i < count; i++) {    
  password.append((userId.charAt(i) - 32) % 10);
}