debug stylesheet,str:tokenize issue

How to debug stylesheet for checking value of variables,params(like
'printf' statements in C)?
I tried using '<xsl:message>',but that message was not displayed even
though it was in the code flow.
Downloading 'oxygen' on my CentOS 5 machine.Will check whether it is
having line by line debugging facility like some XSLT debuggers on
windows.

I am using 'str:tokenize' function in XSL version 1.0.

Here 'args1' and 'args2' are space separated values passed from perl script.
args1=a b c d e   args2=1 2 3 4 5 6 7

I am passing 'value' as '--switch1 <a|b|c|d|e> -switch2 <1|2|3|4|5|6|7>'

So I need to tokenize $value first and add corrosponding value as the
first one in respective combo's followed by corresponding space
separated values(args1|args2)

<xsl:template match="filename">
    <tr>
        <td>   <xsl:value-of select="name"/>        </td>
        <td>    <xsl:value-of select="desc"/>        </td>
        <td>
            <xsl:if test="label = 'combo1'">
                <select name="args1">
                <xsl:call-template name="str:tokenize">
                     <xsl:with-param name="args" select="$args1" />
                </xsl:call-template>
                </select>
            </xsl:if>

            <xsl:if test="label = 'combo2'">
                <select name="args2">
                <xsl:call-template name="str:tokenize">
                     <xsl:with-param name="args" select="$args2" />
                </xsl:call-template>
                </select>
            </xsl:if>
        </td>
    </tr>
</xsl:template>

my.xml

<?xml version='1.0'?>
<?xml-stylesheet href="my.xsl" type="text/xsl"?>
<title>
    <filename>
            <name>name</name>
            <label>combo1</label>
            <Switch>--switch1</Switch>
            <desc>specify name</desc>
    </filename>
    <filename>
            <name>ip</name>
            <label>combo2</label>
            <Switch>--switch2</Switch>
            <desc>specify ip address</desc>
    </filename>
</title>

Yes.As you might have figured out,it is the usual 'EDIT' functionality
of any application.I configured the entity by selecting values from 2
combos and on clicking edit,I should see the previous set one as first
ones,followed by remaining values.

Can I change str:tokenize to achieve this? or without changing it
also,I can achieve the said.
I need to tokenize 'value' to decide first values in 'args1' and 'args2'.
----------------------------
Thanks and Regards,
Himanshu Padmanabhi