When submitting a document to a Records Center with the "Send Document to Repository" workflow action, there is a parameter called "this destination router".

Click the "this destination router" link and enter the full URL to your SharePoint Records Center, including the suffix of _vti_bin/officialfile.asmx.

If you are editing the Collect Signature workflow in SharePoint Designer 2010, and don't see the following action available:

Send Document to Repository

...it could be b/c that workflow is a globally reusable workflow and not specific to a library or content type...which is what the action "Send Document To Repository" needs.

Try these steps:

1. Go to the root SharePoint site and create a content type
2. Go to your target library where you need to do this "Send Document to Repository" action, and associate the content type created in step #1
3. Go to the root SharePoint site
4. Open SharePoint Designer
5. "Copy/Modify" the Collect Signatures SharePoint 2010 Workflow
6. On "Create Reusable Workflow" pop-up / modal window select the bottom dropdown list "Content Type" you created in step #1
7. Now when the new workflow is open, type "Send" to filter back 3 options for your workflow "Actions"
8. You should see "Send Document To Repository" option now available

If you are getting the following error when trying to save a workflow as a template in SharePoint Designer, as I was trying to do with a collect signature workflow:

'the server was unable to create your template'

...try taking out some characters for the new name of the workflow.  That worked in my scenario.

Special thanks to author here for pointing me in the right direction:

http://www.oriolardevol.com/Article/Details/30

You may get an error of "The server could not complete your request" when trying to copy and modify a Collect Signatures Workflow in SharePoint 2010.

Instead of doing this from a sub-site, go to the root site and try the same thing in SharePoint designer.

That fixed my issue.