OK

First check you have added the web service as a submit data connection to
the form you can use a rule to set the web service field to the value of the
drop-down list when the drop-down list is not balnk for example.  To pull the
data back add the web service as receive data and reverse the procedure to
the text box.

Hope this helps, any question let me know

I have tried going back to basics and created a new blank Infopath for
with a drop down List Box (with 3 sample parameter values), a text bo
formatted as integer data type and a button that queries the we
service.
I have added the web service (secondary data connection) as a submi
connection with the parameter option set as the drop down list bo
value.
I have also added the web service as a recieve connection and assigne
the recieve data to the text box.
I have added a submit rule and a query rule to the button properties
however when I preview the form there is no data returned from the we
service when I click the button.
I have also tried to create a basic new form based on the web servic
to both submit and receive data.  Typing a value into the query fiel
and pressing the query button also resulted in no data being returned.
The web service works fine within Visual Studio, prompting for
parameter value and returning the appropriate data.
Other web services where I have 'hard coded' the parameter value int
the SELECT statement work fine within Infopath.
There is obviously something simple I am overlooking - any suggestion
would be appreciated