Can processing rules be applied to concatenate merchandising evar to context data?

Hi everyone, 

Could you please help me debug the following issue with using merchandising and context vars in the processing rule? 

We are passing one conversion variable (evar63) as a merchandising var in the s.products:

s.products = “Category; SKU;;;event85=1;evar63=’id_1’"

ON the same s.t() call, we are passing the current date via context variable ('currdate'):

s.contextData["currdate"] = new Date().toMMDDYYYYString();

Then, we would like to overwrite the original value of evar63 with the concatenated values of evar63 and context data (currdate). The processing rule is:

- If evar63 is Set, then  Overwrite value of evar63 To Concatenated Value of evar63, currdate(Context Data) using a pipe (|) delimiter.

Unfortunately, this setup didn't work and we are still getting the original, not concatenated values in the evar63 report.

I was confused because the Help section mentioned, 'The product string, referrer, and user agent cannot be changed' (http://microsite.omniture.com/t2/help/en_US/reference/processing_rules_about.html). 

Is merchandising evar should be considered a part of product string and can NOT be altered? The Customer Care rep assured it can be since it is available in the drop-down menu of the processing rule. 

Did anyone tried to use merchandising var and context data in the same processing rule?

Thank you!

irina