The Text Block selection through the VIEW question expect a list of elements formatted in the same fashion as the MULTISELECT questions do. Only the Text Block IDs should be encoded in the response.
<xsd:schema targetNamespace="http://example.info/types">
<xsd:simpleType name="question0">
<xsd:restriction base="string" />
</xsd:simpleType>
</xsd:schema>
<xforms:instance>
<response xmlns="">
<question0>@NTAwMw== @NTAwNA==</question0>
</response>
</xforms:instance>
<itp:question>
<itp:paragraph-set>Claims</itp:paragraph-set>
<itp:textblockserver>
<itp:server>textblock-server</itp:server>
<itp:port>7777</itp:port>
<itp:environment>Default</itp:environment>
</itp:textblockserver>
<xforms:select ref="question0">
<xforms:label>Select textblocks</xforms:label>
<xforms:item>
<xforms:label>5003 - Send Invoice</xforms:label>
<xforms:value>@NTAwMw==</xforms:value>
<itp:order>0</itp:order>
</xforms:item>
<xforms:item>
<xforms:label>5004 - Provide Estimate</xforms:label>
<xforms:value>@NTAwNA==</xforms:value>
<itp:order>1</itp:order>
</xforms:item>
<xforms:item>
<xforms:label>5005 - Condition breached - reserve rights</xforms:label>
<xforms:value>@NTAwNQ==</xforms:value>
<itp:order>2</itp:order>
</xforms:item>
… … … …
</xforms:select>
</itp:question>