UseModifier and CommonAdjust

[Ezra Gilbert <egilbert@CYBERNEX.NET>]

I am having alot of trouble setting up my pricing scheme and it all
revolves around being able to modify the price by certain fields in my
database.  My products.asc has the following columns:
code    name    GRS    PER    HOOK    CUP    description
length        price
1          test       3.3      17       .5             .06      This is
a test  7,8,9,10    0

I need to be able to access the fields GRS, PER, HOOK, & CUP in my
CommonAdjust code and consequentially in my usertags.

I had thought that py setting: UseModifier length (for example) i would
be able to access the value of the items length using:
my $item = $Vend::Interpolate::item;
$item->{length}

Except that doesnt work.  My question is, is that how UseModifier is
supposed to work?
If not, can someone give me a method with which I can access the value
of these fields for an item in a usertag?
Will I have to do a database lookup from within my usertag or are the
values im looking for contained or containable in some minivend
variable?

Thank you in advance :)
Ezra Gilbert