Can't seem to get External Field scoring running

[karanveer singh <ka...@gmail.com>]

I want to be able to dynamically change scores without having to
update the entire document.
For this, I started using the External File Field.

I set a fieldType called idRankFile and field called idRank in schema.xml :

<fieldType name="idRankFile" keyField="id" defVal="0" stored="false"
indexed="false" class="solr.ExternalFileField" valType="pfloat" />
<field name="idRank" type="idRankFile" />

Now I set the idRank for various id's in a file called
external_idRank.txt in dataDir :

F8V7067-APL-KIT = 1.0
IW-02 = 10.0
9885A004 = 100.0

Originally, the scores for these 3 id's (for my query) was in reverse order.
Now, I query using the following :

http://localhost:8983/solr/select?indent=on&q=car%20power%20adaptor&fl=id,name&_val_:idRank

However, the order for the results remains the same. It seems it
hasn't taken the external field into account

Any ideas how to do this? Is my query correct?