Always get 401 Unauthorized response when using proxy

Hi,

Our API need proxy to access.
I can call GET resources successfully via browse by using proxy.
Simple of authorization:
Authorization: Digest username="box", realm="commonapi", nonce="1363761489129:c4d34d351f91a53af2b3373d10716dfa", uri="/api/ads", response="ff17f9260fb7b69007f31e6278b1a0bc", opaque="5116378867CAA018FA05542A2B74DC1E", qop=auth, nc=00000001, cnonce="a10f845ebfb470d3"

But When I call same resource via same proxy in soapui 4.5.1.1, always get 401 response.
Authorization send out from soapui 4.5.1.1 pro:
Authorization: Digest username="box", realm="commonapi", nonce="1363761635342:10456db10b08dac04e50047ca91a5912", uri="http://195.78.84.28:8080/api/ads", response="4dce11c1d8f0f8efc7c8fb27439a1c6d", qop=auth, nc=00000001, cnonce="d15498bca869a5a5ac447050468425e3", opaque="5116378867CAA018FA05542A2B74DC1E"

Also, "Authenticate Preemptively" is uncheck.

I also tried other two authorisation type in AUT tab, still doesn't work.

Please advice me!!!