Search & Replace + Redirect with Mod_Rewrite?

[VikR]

I need to change the variable names in query strings. This is because I need to get two different supplier companies talking to each other. (One supplier uses variable names that the other supplier doesn't recognize).

So I'm getting supplier A to send the URL to one of my domains, where I can change the variable names in the query string, and then redirect to the web site of supplier B.

For example, I'd like to change:

http://www.my_domain_name.com/wsb.dll/s/12345?DDR2=test_2_data&DDR3=
test_3_data

...to:

https://supplier_B.com/wsb.dll/s/12345?wsb5=test_2_data&wsb6= test_3_data

Here's my current mod rewrite code, which gives me a "Internal Server Error" message:

Options +FollowSymLinks
Options +Indexes
RewriteEngine On

RewriteRule ^(.*)DDR2(.*)$ $1wsb5$2 [NC]

RewriteRule ^(.*)DDR3(.*)$ $1wsb6$2 [NC,L]

Redirect (.*)my_domain_name.com/wsb.dll/(.*) $supplier_B.com/wsb.dll/$2

What is the correct mod_rewrite code to do this?

Thanks very much in advance to all for any info.