You need to pass on those parameters also. As those parameters will be used to paginate the transactions if those are very high in numbers.
For e.g. if the response is having
Number of hits = 1300 (From executeUserSearchRequest
API)
then call getUserTransactions
in loop with
1st call StartNumber = 1 EndNumber = 500
2nd call StartNumber = 501 EndNumber = 1000
3rd call StartNumber = 1001 EndNumber = 1300
Meanwhile we'll get that corrected over the portal that those fields are mandatory.