Is there a way to map/translate a pattern-lock to a numeric PIN?
I downloaded the Android source and found the answer. The wild guess turns out to be right. This is the mapping:

0 1 2
3 4 5
6 7 8


If your pattern is from top-left to top-right (0->1->2) then down to bottom-right (2->5->8), the string version of the password is "01258".

The source for this comes from LockPatternUtils in package com.android.internal.widget:

/**
 * Serialize a pattern.
 * @param pattern The pattern.
 * @return The pattern in string form.
 */
public static String patternToString(List&lt;LockPatternView.Cell&gt; pattern) {
    if (pattern == null) {
        return "";
    }
    final int patternSize = pattern.size();

    byte[] res = new byte[patternSize];
    for (int i = 0; i &lt; patternSize; i++) {
        LockPatternView.Cell cell = pattern.get(i);
        res[i] = (byte) (cell.getRow() * 3 + cell.getColumn());
    }
    return new String(res);
}


where the rows and columns are both {0,1,2}.

However, as I said in my question, I tried this mapping with my pattern, and it doesn't work to unlock my encryption. This turned out to be a dead end, but I hope this answer is helpful to others with a similar problem. (Note again that the other person who had this problem also tried to find the pattern-lock to PIN mapping, but the answer wasn't out there.)