Leading Zeros BPC 10 Transformation

I'm loading Material Masterdata from BW.

My transformation mapping contains this line:

ID=0CO_AREA+0PROFIT_CTR+ID

I want to have a result like:

10000000100002000000000004006701

Works fine for numerical materialnumbers

With non-numerical numbers i don't get the leading zeros

1000000021420750150-51

I tried it with *Pad

ID=0CO_AREA+0PROFIT_CTR+*Pad(ID,18,L,0)

but getting Validation error

[Zeile 14] '0' nicht erwartet an Position 35 in der Zuordnungsformel [0CO_AREA+0PROFIT_CTR+*Pad(ID,18,L,0)]

I've also tried to user a conversion file but it seems that the conversion file only converts the already concatenated ID from the mapping.

Any ideas how to solve this?