Check for positive and negative about in a XSL StyleSheet

Hi

I have a xml that I am Transforming but one element is an amount field that contains positive's and negatives. I want to know how can I check for positive's and negatives in a XSL StyleSheet

here is my xml
<?xml version="1.0" encoding="utf-8"?><transferupload><transfer><Currency>USD</Currency><LegalEntity>xxxx</LegalEntity><Accountid>1020</Accountid><Movement>-111390.73</Movement><ValueDate>2011-05-16</ValueDate><Narration>CFC Transaction 1300192643504</Narration><Counterparty>xx TREASURY</Counterparty></transfer></transferupload>

<?xml version="1.0" encoding="utf-8"?><transferupload><transfer><Currency>USD</Currency><LegalEntity>XXX</LegalEntity><Accountid>1020</Accountid><Movement>111390.73</Movement><ValueDate>2011-05-16</ValueDate><Narration>CFC Transaction 1300192643504</Narration><Counterparty>XXXXX TREASURY</Counterparty></transfer></transferupload>

Here is my XSL StyleSheet to get my Movement element
                                    <calypso:principal>
                                          <xsl:value-of select="transferupload/transfer/Movement"/>
                                    </calypso:principal>

Now I can to check in element quantity for positive amounts and negatives abouts
                  <calypso:quantity>
                              <xsl:value-of select="if (@Movement < ) then '-1.0'
                                    else '1.0'"/>
                        </calypso:quantity>