The easiest without understnding the problem fully is to attach the same form to the sub workflow So your main workflow package will have a form(s).Your subworkflow also needs to reference the same forms.Now on the painter view of the main workflow double click on your sub workflow step.Assuming your main workflow and subworkflow are consistent in thier package definitions you should see tabs
General,Comments,Attachments,Attributes,Forms,EventScripts (optional only if your software has it)etc.Click on the forms option and more than likely livelink will ask you whether or not to pass form data between the main and sub.
I think it is called Form association or Data Mapping or something like that.I always make sure that there is one to one correspondence and there is an auto link button too.Autolink will not create missing filds in sub but does show you where the inconsistencies are
Come to think of it is this what you are asking ?
Everybody is ignorant, only on different subjects. - Will Rogers
appnair