Opportunity campaign ID value help for a custom field

Hi All,

I have a requirement to attach the same advance search value help that is there for campaign id field. this custom field will behave similar to campaign id with some other changes. I can see method method 'EH_ONVHELP_CAMPAIGN_ID' of impl class implemented in class'CL_BTSLS_ADVS_CNTRL is getting called as event handler. I can not call the class method directly due to the attributes. Can you please tell me how can I implement the same value help?

Thanks,

JC