Unified XML Request -> Legacy XML Response?

I must be doing something really simple wrong.  I constructed a request in new
XML format, but getting Legacy XML response.  Can someone tell me what I missed?
 Any help is really appreciated.

Below are the URL, headers, request and response I got,

------------ 8< ------------
URI: https://api.sandbox.ebay.com/ws/api.dll

X-EBAY-API-COMPATIBILITY-LEVEL: 457
X-EBAY-API-DEV-NAME: H5B6859J4C886D4971DWVH21YKG79M
X-EBAY-API-APP-NAME: EARTHLINKIP4152419S7KCH965GSJ4
X-EBAY-API-CERT-NAME: B3DBG6EI798$4E14T2BWO-KNR35E89
X-EBAY-API-SESSION-CERTIFICATE:
H5B6859J4C886D4971DWVH21YKG79M;EARTHLINKIP4152419S7KCH965GSJ4;B3DBG6EI798$4E14T2
BWO-KNR35E89
X-EBAY-API-CALL-NAME: GeteBayDetailsRequest
X-EBAY-API-SITEID: 0
Content-Type: text/xml

<?xml version="1.0" encoding="utf-8"?>
<GeteBayDetailsRequest xmlns="urn:ebay:apis:eBLBaseComponents">
<RequesterCredentials>
<eBayAuthToken>AgAAAA**AQAAAA**aAAAAA**nKNWRA**nY+sHZ2PrBmdj6wVnY+sEZ2PrA2
dj6wJnY+lCJeDoQ2dj6x9nY+seQ**CB8AAA**OAMAAA**/FMbU2RD8v9QJJG1iaFj+sCSpkEL6WyTM9U
n4AEs4lbdO1+wzE5cV9VdRSXfUqDzHv7rsIiTpL1GOsoBNHRSeRTt0P4YlShjlmWOAQPe6yg26joDI/s
3DfhUzzLt2vSUN/r4O6MyZiREDNZeojg7o6FFGPSydYv2z7yvPK8883dhhE0/xbQn14WV8JojsOdTSVP
Ab3prtQcP35Pjnc+wRYfkDXbhzXhEDCQyPSeV+LbD6N9PDp2mV9W2hwPNYZK3hR2zbB8pZmgnID/0IOk
fmm6VtcNjmu6HQkRFT4BdbVGeOMsk+bJU5eZ+1lNzI562/mPcfiQAapjLxJE8gB8ZPMj6HDkNEbn4Vga
pBDp+foxR07smUxpxk7Kwhh271hKoCI+ENJdodE6wHp7K2VwNJGsClSiDHKPouzFHcn7ToG7GQZbN4kC
RkXs2/6ymAfyrDWZZyAMW+Vas2R5AcUv9nnlYQRPzIqex/FwFmLUPbqsgNy9oihstyt7jE6buvcFkFUm
lph/mv0InNypvJoKoj1YMaZ1/x2wThVHkciCh9euUznif9DLmTFpfv3O+++rMj3VwbYXFn3Jxf+vgwNv
aWANNsIfGJYIEgCA6JH2So33bHsJDDuaJmrIhxwGOt4Lg2NMEeQC3mCePy+K1jyrefvBwbVYFbpAODY8
ycEjWeOUMFttmkGHdkA/RWm1e6ZYrJ8060KUqMnt/3Pr0RgzZhsjAcrPvRof5Yf+YyeEhlgJIcD0Dzxh
0UztFU0QhT2elaG/G2vtPJMG7MTndpwQ9/aMJpagIU80Autn/4GneTJ1c+cJo4PblKA**</eBayAu
thToken>
</RequesterCredentials>
<Version>457</Version>
<DetailName>URLDetails</DetailName>
</GeteBayDetailsRequest>

<?xml version="1.0" encoding="utf-8" ?>
<eBay>
<EBayTime>2006-05-17 20:10:25</EBayTime>
<Errors>
<Error><Code>2</Code>
<ErrorClass>RequestError</ErrorClass>
<SeverityCode>1</SeverityCode>
<Severity>SeriousError</Severity><Line>0</Line><Colum
n>0</Column><ShortMessage><![CDATA[ Unsupported verb.
]]></ShortMessage></Error>
</Errors>
</eBay>