IWS and input parameters...

I want to have a filter(s) for my api.
An individual filter is defined as

dcl-ds filterTmp template qualified;
type char(20);
value char(20);
end-ds;

But there may be multiple occurrences of filter. For example,

'Warehouse': '95,96,97'
'Type':'Shipments'
'DateRange': 'LastWeek'

I was hoping to do something like
dcl-pi *n;
pFilterDs likeds(filterTmp) dim(10) const;
transactionDs_length int(10);
transactionsDs likeds(transactionsTmp) dim(1000);
httpStatus like(httpStatusTmp);
httpHeaders like(httpHeadersTmp) dim(10);
end-pi;

But when I try this on Step 5 of 9 on the Deploy New Service Wizard I get
error
*Error:* ZUI_54411: The HTTP method must be PUT or POST when there is an
input parameter that is not being injected with a value.

How should I be doing this?

Thanks, Rob