using variable when using ISABOUT

Question

I found this thread about the same problem, but the proposed solution doesn't work for me Can I use a variable when using ISABOUT?

My code is fairly simple:

DECLARE @SearchTerm varchar(8000)
set @SearchTerm = 'IC_PARTY'
set @SearchTerm = @SearchTerm + '*'
select 
        ct1.rank AS NAME_RANK,
        t.id,
        t.name,
        t.text_short,
        t.text_long,
        t.text_search,
        t.searchtype,
        t.type,
        t.notice        
from [CMRUSER].[WK_FULLTEXT_D_UQID] t

left join CONTAINSTABLE([CMRUSER].[WK_FULLTEXT_D_UQID], NAME_ND, N'ISABOUT(' + @SearchTerm + 'WEIGHT(0.1))') ct1
ON t.id = ct1.[KEY]

What I need to do is pass a variable into ISABOUT(), but im getting error "an expression of non-boolean type specified in a context where a condition is expected"

Anybody could advise on how to approach this problem?

I will have 4 same joins as this one. Each for every searched columns and they will also be weighted.