Multiple choice items with custom format

[luxid]

Using html file, I set multiple choice items with Item type of "Custom".
e.g.,
<input type="checkbox" name="<ml.varname>_03" value="1">
<input type="checkbox" name="<ml.varname>_03" value="2">
<input type="checkbox" name="<ml.varname>_03" value="3">

The problem is that only the last selection of checkbox is recorded.
For example, if 1 and 3 are chosen, only 3 is recorded.

How can I make all checked items recorded?

[Trevor Newell]

It seems as though this problem may be able to be remedied by implementing three variables to intercept the data, and then changing the HTML as followed:
<input type="checkbox" name="<ml.varname>_01" value="1">
<input type="checkbox" name="<ml.varname>_02" value="2">
<input type="checkbox" name="<ml.varname>_03" value="3">

Does this make sense?