Unable to replace with null by using search_replace function

Hi All,

In my custom function I am facing some strange issue.

I am gettign some special charecters in the input I need to change them to null as below:

Input : STE: B12

Req Output: STE B12

Current output: STENULL B12

Please find below code which I am using :

search_replace([], ['SR_STRING'], ['no'], [], [$P_AddressLine], [$P_AddressLine])  SET (

"internal_table" = '<?xml version="1.0" encoding="UTF-8"?>

<searchTable>

<entry>

<search>;</search>

<replace>NULL</replace>

</entry>

<entry>

<search>:</search>

<replace>Null</replace>

</entry>

Thanks,

Sreenivas