Javascript calculation problems

I have the script below, it takes a number of check boxes that are options with prices to a main number for example I have a main car price, and adding three different option groups to give me the new total.

<script type="text/javascript">
                            function createOrder()
                            {
                            optionValues=document.forms[0].optionValues
                            txt=0
                            for (i=0;i<optionValues.length;++ i)
                            {
                            if (optionValues[i].checked)
                            {
                            txt=Number(txt) + Number(optionValues[i].value)
                            ntxt=Number(txt)
                            }
                            }
                            onum=Number(0)
                            totalnum    = onum + ntxt
                            ntotalnum   = Math.round(totalnum*100)/100;
                            document.getElementById("oValues").value = ntotalnum
                            }
                            </script>
The option boxes look like this
<input checked="checked" onclick="createOrder()" name="optionValues" type="checkbox" value=VALUE />
Then there is the box that gets written the value
<input type="text" id="oValues" size="15" class="valueBox">

This code works great, it is clean and fast to update. I just have 1 main problems.
With that code and having all checkboxes named the same I can not pass this value on in a form element to another page.

Any ideas how to rewrite the code so that the element names are different so I can pass them through the form. I have tried a number or things and when I do it, it will not pass any values.

Kevin