Absence of the UInt32 field in fix message when we Initialize FieldUInt32 to a Null Value while encoding

[mounika-allagadda]

Hi,

I am working on the encoding a fast message.
I have an optional uint32 field in the template which should be initialized to NULL.

So, while encoding I used createNull() function.
msg->addField(identity_AppID, Messages::FieldUInt32::createNull());

But while debugging I decoded it immediately and I see this field absent.

In case of string, there is a possibility to give empty string using create() function and in the decoded message that field exists with empty value, which is a required feature for me.
msg->addField(identity_NewPwd, Messages::FieldAscii::create(""));

The decoded message is: 
35=A|52=20160503-10:15:08.000|108=30|553=MDF|554=cse|925=|

Here 925 is NewPwd, and AppID(1180) is absent.
I want AppID in the same way as 925.

Can someone help me with this?

Thanks in advance.