vb6 implementation for icmpsendecho2 - vb6

Question

I'm trying to implement a Ping program in vb6 which works for both IPv4 & IPv6 addresses. The IPv4 implementation uses IcmpSendEcho which is working fine, but the IPv6 implementation uses Icmp6SendEcho2 and I'm having a lot of difficulty getting it to work.
The function call works fine and it does not error out but the return value is always 0, and GetLastError returns 0 indicating that no errors occurred
https://msdn.microsoft.com/en-us/library/windows/desktop/aa366041(v=vs.85).aspx
The process I follow is as follows:
Load the windows sockets dll by calling WSAStartup
Open a port handle via a call to Icmp6CreateHandle
Send a ICMP ECHO message via a call to Icmp6SendEcho2 and analyze the response
close the port handle by calling IcmpCloseHandle
Unload dll by calling WSACleanup
The definition of Icmp6SendEcho2 is as follows
Private Declare Function Icmp6SendEcho2 Lib "Iphlpapi.dll" _
(ByVal IcmpHandle As Long, _
ByVal EventtoRaise As Long, _
ByVal ApcRoutine As Long, _
ByVal ApcContext As Long, _
ByVal SourceAddressPointer As Long, _
ByVal DestinationAddressPointer As Long, _
ByVal RequestData As String, _
ByVal RequestSize As Long, _
ByVal RequestOptions As Long, _
ReplyBuffer As ICMPV6_ECHO_REPLY, _
ByVal ReplySize As Long, _
ByVal timeOut As Long) As Long
Where ICMPV6_ECHO_REPLY is defined as follows
Private Type ICMPV6_ECHO_REPLY
Address As IPV6_ADDRESS
Status As Long
RoundTripTime As Long
End Type
Private Type IPV6_ADDRESS
sin6_port As Integer
sin6_flowinfo As Long
sin6_addr(1 To 8) As Integer
sin6_scope_id As Long
End Type
The call to Icmp6SendEcho2 is made as follows
lPingResponse = Icmp6SendEcho2(lPortHandle, 0, 0, 0, VarPtr(SourceAddress), VarPtr(DestinationAddress), sMessage, Len(sMessage), 0, Reply, Len(Reply), timeOut)
I used the following link for implementing Ping for IPv4
https://support.microsoft.com/en-us/kb/300197
Any help would be awesome
Nish

Answer 1

The issue was associated with there not being a sufficient buffer to get the response. Changing the response structure to something like this did the trick
Private Type ICMPV6_ECHO_REPLY
Address As IPV6_ADDRESS
Status As Long
RoundTripTime As Long
data(0 To 1023) As Byte
End Type